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The immunologically privileged status of the anterior chamber of the eye has been confirmed on the basis of skin and thyroid allografts with use of inbred strains of rats. Skin grafts, transplanted across both major and minor histocompatibility barriers, enjoy prolonged survival within the anterior chamber. However, several factors have been found to restrict the privilege exhibited by this site: the magnitude of the immunogenetic disparity between donor and recipient, graft size, type of tissue grafted, and, at least in the case of thyroid grafts, the endocrine status of the host. Although a defect in the afferent limb of the immune response has been the popular explanation offered for immunological privilege in an alymphatic site, this was not the basis of the privilege encountered in the anterior chamber. Furthermore, because the efferent limb of the immunological reflex are within the anterior chamber has been demonstrated to be intact, it was suggested that the unique properties of the anterior chamber may depend upon the forced intravascular presentation of antigen and consequent aberrant central processing.

Kock's continent ileostomy is a well-established technique, however, it is technically difficult to construct and has a high incidence of complications. This study evaluates a new type of mucosal valve constructed in continuity with an intestinal reservoir. The valve is created along the antimesenteric border of the efferent limb 0.5 cm distal to the reservoir. The seromuscular layer is “stripped” from the mucosal layer for 50 per cent of the bowel circumference and then excised. The remaining seromuscular borders are then sutured to the apex of the pouch and along the antimesenteric border of the afferent limb. In this way the valve is created and, upon distention of the afferent limb and apex of the pouch, the valve closes. In seven dogs such a continent ileostomy was constructed and all were clinically continent. The reservoirs were intubated through the ileostomy two to three times a day. The mean volume aspirated was 143 ml/day. After eight weeks, radiographic and volume-pressure studies were performed. Prior to sacrifice, increasing volumes of barium were instilled into each pouch via the afferent limb and radiographs were taken: these studies confirmed the continence in all seven ileostomies. Following this the reservoirs were intubated and the instilled barium was aspirated. Then Ringer's solution was instilled into each pouch with continuous intrapouch pressure measurements. The pressure remained at 0 cm H2O until a mean volume of 243 ml was exceeded. The mean volume at which incontinence occurred was 415 ml.

Le recueil de ľelectrogramme intracardiaque donne ľinformation necessaire aux systemes de stimulation a la demande. Les troubles du recueil surviennent dans pres de 50% de stimulateurs unipolaires, ceux de ľoreillette sont encore plus frequents. Le recueil par electrode orthogonale ne demande pas de contact avec le myocarde et on obtient de hauts potentiels ?origine auriciilaire avec rejection totale des pontentiels ventriculaires. Ce systeme permet la sequence ?activation aussi bien que la verification de la capture. Intracardiac electrogram sensing is the afferent limb of demand pacing systems. Under- and over-sensing at the ventricular level has been demonstrated in almost 50% of implanted unipolar pulse generators, and atrial eJectrogram sensing problems are more common. A unique dedicated sensor employing noncontacting and circumferentially placed orthogonal electrodes was tested at both the atrial and ventricular levels. Electrograms demonstrated voltages similar to those recorded from contacting electrodes, but with complete far-field rejection of signals from the opposite chamber. Orthogonal electrograms allowed for activation sequencing and capture verification as well.

The effects of 4th ventricular injections of phlorizin and 5-thioglucose (5-TG) on feeding, plasma glucose, and plasma insulin levels were determined. Fourth ventricular applications of phlorizin (13 micrograms) and 5-TG (150 and 210 micrograms) were equally effective in stimulating feeding. Systemic injections of phlorizin (13 micrograms) did not stimulate feeding. In the absence of food, hyperglycemia was elicited by 4th ventricular injections of 5-TG. In contrast, the dose of phlorizin that stimulated feeding, did not produce hyperglycemia. Basal plasma insulin levels were not affected by either of the 4th ventricular injections. These data indicate that activation of caudal brainstem metabolic interoceptors provides an afferent limb for the production of compensatory responses and that behavioral and autonomic compensatory responses can be activated independently. The glucodynamic action of phlorizin appears selective for that mechanism mediating the behavioral compensatory response of feeding in contrast to the dual effects produced by 5-TG. These and other data suggest that different caudal brainstem mechanisms control behavioral and autonomic compensatory responses.

The occurrence of sulfites in foods, drug products, and the environment; the characteristics of sulfite-sensitivity reactions; and the management of sulfite-sensitive individuals are reviewed. Sulfites are used in foods, beverages, and pharmaceuticals for their antioxidant properties; they are frequently used in restaurant foods to keep vegetables and fruits looking fresh. Beer, wine, and dried, canned, or frozen fruits often contain sulfites, and seafood and fried potatoes are often prepared with these agents. Sulfites are also present as pollutants in the atmosphere. The incidence of sulfite sensitivity is unknown, but the condition is being recognized with increasing frequency. Bronchospasm is sometimes induced by sulfites in sensitive individuals, and anaphylaxis and death have been reported. Immediate or delayed reactions may occur. The mechanism of toxicity is unknown but is thought to be sulfite-induced stimulation of the afferent limb of the cholinergic reflex. Clinical management is based on avoiding strenuous exercise on days when atmospheric pollution is high and on avoiding foods and drug products containing sulfites. Treatment of sulfite-sensitivity reactions is usually supportive; subcutaneous epinephrine has been effective in some patients. Several drugs have been used investigationally to prevent sulfite-sensitivity reactions. However, few data are available to evaluate their efficacy. Sulfites may induce bronchospasm and anaphylaxis in sensitive individuals. These people should avoid foods and drug products containing sulfites.

A patient with recurrent squamous carcinoma metastatic to the neck after radical neck dissection and high dose radiation therapy developed paroxysmal hypotensive episodes that were severe, spontaneous and characterised by suppressed sympathetic but not enhanced parasympathetic activity. Intravenous pressors were successful in treating acute episodes but neither drug therapy nor surgical neck exploration reliably prevented syncopal attacks. Glossopharyngeal and/or vagal nerve infiltration by tumour with episodic activation of the afferent limb of the baroreflex arc producing vasodilatation primarily due to sympathetic withdrawal is the likely mechanism of life threatening syncope in this patient.

Cough is a complex physiologic event that protects the lungs from mechanical, chemical, and thermal injury. It is a normal reflex and therefore helps humans to adapt to an ever-changing environment. Cough can also be a pathologic reflex in that it may be an important and often the only sign of serious disease, may significantly contribute to the spread of airborne infection, and in some instances, may result in severe functional or structural damage to the organism. This article focuses on the pathophysiology of the afferent limb of the cough reflex, including a discussion of the causes, the diagnostic workup, and the treatment of cough.

Summary Ten unoperated control patients and 18 patients with Billroth II subtotal gastrectomies, 11 without and 7 with steatorrhea, have been studied. Duodenal fluid in the control patients and afferent loop fluid in the postgastrectomy patients were subjected to quantitative bacterial cultures. Fat absorption was estimated by microscopic stool examinations, I 131 -triolein excretion studies, and, more recently, fat balance measurements. Bacterial counts in the unoperated control patients showed a mean of 18,940 colonies per cc. In the 11 postgastrectomy patients without evidence of steatorrhea the mean of the bacterial counts of afferent limb fluid was 625,210 colonies per cc. Streptococci predominated in 9 of these 11 patients. In 7 patients with steatorrhea, the mean colony count was 162,843,000 colonies per cc. The 2 patients with most severe steatorrhea had the highest bacterial counts—250,000,000 and 750,000,000 colonies per cc., respectively. In all steatorrheic patients the predominating organism was a Gram-negative bacillus, the flora generally resembling colonic flora in both quantity and quality. In the 2 most severely affected patients specific antibiotic therapy based on sensitivity determinations of cultured bacteria resulted in striking improvement in weight and fat absorption, which coincided with a return of the afferent limb flora to normal. Analysis of clinical data revealed that postgastrectomy steatorrhea tends to occur in patients with long, often antiperistaltic, poorly draining afferent limbs, where prolonged stasis permits the establishment of a resident bacterial flora. An analogy between postgastrectomy steatorrhea and the blind loop syndrome is suggested.

Experimental data are presented which suggest the existence of baroreceptors in the adrenal gland and the kidney. A hypothesis is developed that considers these receptors as part of the afferent limb of a set of reflex systems concerned with the regional control of blood flow. A distinction is made between regional or local systems and general systems within the organism. Functional attributes based on evolutionary considerations are given to these systems. The role of local or regional feedback systems concerned with hemeostasis is emphasized.

Twenty-three cases of afferent limb obstruction are reviewed and the X-ray appearances of two cases are presented. The number of radiological observations is too small to enable one to make hard and fast rules for the diagnosis. It is felt that plain films of the abdomen are a valuable diagnostic aid. A soft tissue mass in the upper abdomen is a characteristic feature, particularly in the absence of pathological fluid levels. If this finding is assessed in the light of the history, symptoms and signs, the correct diagnosis should be arrived at without difficulty.

Jaw reflexes and masseter electromyograms were studied in five patients with mesencephalic and 11 patients with pontine lesions, vascular or tumorous in nature. In the former group jaw reflexes were abnormal, being delayed or absent, whereas masseter electromyograms were normal. In the latter group, both jaw reflexes and masseter EMG, showing denervation, were abnormal in six and both normal in five cases. It is suggested that the afferent limb of the human jaw reflex passes through the mesencephalic trigeminal nucleus. The methods proved to be valuable in the diagnosis of mesencephalic and pontine lesions involving the fifth cranial nerve.

This preliminary report details the radiologists' contribution to the combined surgical—radiologic approach to maintaining patency of the biliary tree that may benefit certain categories of patients with biliary strictures. We have accessed the biliary tree through the stomatized afferent limb of a side to side biliary jejunal anastomosis in 18 patients. Our early experience with this technique suggests that we may be able to maintain patency of biliary strictures without the need for permanent indwelling catheters or stents.

Lymphocyte blastogenesis was used as an assay of Immune RNA (I-RNA) activity. Normal, non-immune human lymphocytes following incubation with xenogeneic antitumor I-RNA extracted from the lymphoid organs of specifically immunized sheep underwent blastogenesis when exposed to solubilized human tumor antigens in vitro. Blastogenic responses were, unexpectedly, relatively specific for the tumor type used to immunize the I-RNA donor sheep. No significant blastogenic responses were elicited by the I-RNA extracts or by the antigen preparations themselves. This study suggests that normal, human lymphocytes incubated (‘sensitized’) with I-RNA, in vitro, behave, in terms of antigen recognition, like lymphocytes which have previously been sensitized to tumor antigens and demonstrates that xenogeneic Immune RNA will mediate ‘afferent limb’ immune responses to human tumor antigens.

The regulation of body temperature is often conceptualized as a negative feedback control system complete with afferent limb, integrating area and effector limb. Most vertebrates regulate body temperature and these animals have been classified into two groups - ectotherms and endotherms. Ectotherms rely largely on behavioural responses to raise or lower their body temperature. Among the vertebrates, most fishes, amphibians and reptiles are ectotherms. Endotherms rely to a large extent on physiological responses to raise or lower their body temperature. Often this includes increasing or decreasing metabolic heat production. Birds and mammals are endotherms. The distinction between endotherms and ectotherms, however, is not absolute. For example, a large percentage of the thermoregulatory effector responses of endotherms is behavioural modifications designed to avoid extremes in temperature. This is why most desert animals are nocturnal, or in cold climates many animals either migrate to warmer climates, avoid the intense cold by burrowing under the snow or hibernate. The result of these numerous thermoregulatory effector responses is that the deep-body temperature of both endotherms and ectotherms is regulated around a hypothetical thermoregulatory set-point.

A significant depression in cell-mediated immunity as measured by lymphoproliferative responses to phytohemagglutinin and responsiveness to mixed lymphocyte culture was observed when adult lymphocytes or cord blood lymphocytes were incubated with increasing concentrations of bilirubin. The inhibitory effect of bilirubin could only be demonstrated with suboptimal concentrations of PHA (0.01 and 0.005%) and was more marked in premature infants than in term neonates or adults. This effect was partially reversible after short preincubation with bilirubin, but was more protracted with preincubations of 24 hours or more. Inhibition of MLC responsiveness of 80.1 plus or minus 5.1% was also demonstrated at a bilirubin concentration of 20 mg/dl. Specific cytotoxicity to rubella virus-infected cells, measured by a 51Cr-release microassay, was not found to be depressed. Bilirubin thus appears to have an inhibitory effect on immune responsiveness which is greater on the afferent limb than on the effrent limb of immunity.

Treatment of large burns would be simplified by the development of a nonsensitizing allograft which would survive permanently. In our hands, in vitro immune modification of the allograft has prolonged graft survival in mice across major histocompatibility barriers (H-2d to H-2b) by 36% (steroid pretreatment) and 25% (monoclonal antibody to the Iad antigen found on donor Langerhans cells). To our knowledge, monoclonal antibody has not been employed in this capacity previously. Double grafting studies suggest that neither MK-D6 nor steroids enhance graft survival by systemic immunosuppression. Moreover, MK-D6 acts upon the afferent limb of the immune response while steroids interrupt the efferent limb (and probably the afferent limb). These effects are not additive. This modest improvement in allograft survival may have profound importance since allografts supported briefly by host immunosuppression have gone on to indefinite survival in burn victims without further immunologic intervention. This improvement in allograft survival is of fundamental immunologic interest. If synergistic pretreatments can be found, it may ultimately allow allografting of burn victims with the expectation of indefinite graft survival.

A recent clinical case afforded an opportunity to study the effects of duodenal stimulation on plasma human pancreatic polypeptide and gastrin concentrations, independent of gastric stimulation. A distension stimulus was provided by rapid injection of 100 ml of water and saline via a T-tube into an isolated duodenal afferent limb. In a third experiment, the saline contained 200 pg/ml of heptadeca-peptide human gastrin. Within 2 min after each injection, a rapid rise in circulating human pancreatic polypeptide levels appeared that fell promptly towards basal thereafter. Injections of 100 ml of Flexical, a supplemental tube feeding, resulted in a biphasic human pancreatic polypeptide response, the initial peak comparable to that seen following distension with water, saline, or saline containing gastrin, and a second peak of much greater magnitude and duration followed the initial peak. Plasma gastrin concentrations were not influenced following any of the stimuli. Duodenal distension alone may induce an early transient increase in plasma human pancreatic polypeptide concentrations, while intraduodenal nutrients per se may induce a later increment of greater magnitude and duration.

Contact sensitivity to dinitro-fluorobenzene in the mouse is a form of delayed-type hypersensitivity. This reaction is closely regulated. Tolerance to contact sensitivity is mediated by at least 2 mechanisms, tolerance without demonstrable suppressor cells and tolerance with suppressor T cells. Suppressor T cells can inhibit either the afferent limb of sensitization or the efferent (elicitation) phase. These cells probably operate via soluble suppressor factors and require auxiliary cells. The duration of contact sensitivity itself is controlled by another mechanism, which is antibody. This antibody is directed against the T cells responsible for the delayed hypersensitivity state (TDH), and down-regulate these cells. It is antigen-specific and has the properties of an antireceptor (anti-idiotypic) antibody.

A combined surgical and radiological approach to the management of complex biliary strictures is described. Radiological access for stricture dilatation or stone extraction is created at the time of surgery either by insertion of a transhepatic u-tube or superficial fixation of the afferent limb of the roux-en-y loop. Each of seven patients treated in this way had multiple complicating factors known to adversely affect the outcome of operative repair. Five of the seven have had an excellent outcome at a median follow-up of 15 months (mean 21 months, range 2–39 months).

Treatment of newborn rats with capsaicin (0.16 mmol/kg) is known to cause a permanent degeneration of mainly unmyelinated afferent neurons. In this study, postoperative ileus and ileus produced by peritoneal irritation with iodine were investigated in adult rats treated with capsaicin as neonates. It was found that in capsaicin-treated rats both forms of ileus, measured as inhibition of gastrointestinal transit, were significantly reduced as compared with vehicle-treated control animals. Adrenoceptor blockade in untreated rats reduced the ileus in response to peritoneal irritation to approximately the same degree as treatment with capsaicin. In capsaicin-treated rats, however, adrenoceptor blockade was without effect on the irritation-induced ileus. It is concluded that ileus in response to surgery or peritoneal irritation is due, at least in part, to activation of a neural reflex. The afferent limb of this reflex may be constituted by capsaicin-sensitive nerve fibers, whereas the efferent limb seems to involve sympathetic adrenergic neurons.

Hepaticodochojejunostomy with an afferent limb constructed to provide a permanent access route for retrograde biliary dilation has been described. The computed tomographic (CT) scans of 12 patients who had undergone this procedure were reviewed. The appearance of the afferent limb from its position within the subcutaneous tissues to its anastomosis with the biliary tree is described and illustrated. Recognition of the limb as a surgical pathway is important because familiarity with its anatomy will avoid errors in CT interpretation and aid in successful transjejunal catheterization of the bile ducts.

Publisher Summary The purpose of this chapter is to focuses on the studies that demonstrate the presence of rapidly adapting and slowly adapting mechanoreceptors capable of responding, albeit in a manner somewhat different from receptors found in the digits, to a wide variety of indentations efferent modulation of penile mechanoreceptor activity. The mammalian penis is innervated by sensory receptors. The mechanoreceptors, responsible for tactile sensation and the afferent limb of the spinal sexual reflexes, are studied physiologically in several species using computer controlled mechanostimulators. The upward shift in the indentation velocity coding curves described in a study is again probably because of the decrease in penile compliance during a state of erection. In short, the results of this preliminary study demonstrate that many of the mechanoreceptors in the penis of the rat can respond to internal as well as external stimuli to the penis and their stimulus—response characteristics can be modulated with efferent stimulation of the autonomic and somatic components of erection.

The mechanism of the tussive action of 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP) was investigated in terms of the sensory, central coordinating and motor components of the cough reflex. DMPP was found to evoke cough by an action on the afferent limb involving chemoreceptors of the carotid and possibly pulmonary areas. The tussive response to DMPP appeared to be unrelated to its classical action on autonomic ganglia.

In order to produce the QRS loop similar to that of TOYAMA-SUZUKI's syndrome or its transitional type, the solution of cresol or isoproterenol was injected intravenously in dog. In Cresol Group, the afferent limb of the QRS loop was dislocated right-postero-superiorly and the QRS loop resembled to that of the transition-al type. In Isoproterenol Group, the QRS loop was displaced completely postero-superiorly and was very similar to that of T. S. syndrome. In both groups, the localized inferior infarction was not found in autopsy. Therefore, it can be assumed that the superior displacement, of the QRS loop in T. S. syndrome or its transitional type was not induced by the localized inferior infarction but by the intraventricular conduction disturbance.

The afferent limb of a rapid response system is responsible for monitoring the patient, detecting deterioration and triggering a clinical response. This chapter describes the observations, early warning systems and calling criteria used to identify the sick or deteriorating patient. Failures in the individual components of the afferent limb are common and frequently result in potentially avoidable, adverse clinical outcomes. We describe the current shortfalls of the afferent limb and consider the actions required to improve its functioning including: improving regular patient monitoring and assessment; ensuring the accurate measurement and recording of vital signs; and enabling the timely calling of a rapid response team. The chapter also considers the role of technology in improving the functioning of the afferent limb.

sixth leucocyte culture conference, New York, 1972, Academic Press, Inc. 3. Rosenber SA, and David, JR: Inhibition of leukocyte migration: An evaluation of this in vitro assay of delayed hypersensitivity in man to a soluble antigen, J Immunol 105:1447, 1970. 4. Wybran J, Carr MC, and Fudenberg HH: The human rosette-forming cell as a marker of a popul~ttion of thymus-derived cells, J Clin Invest 51:2537, 1972. 5. Lawrence HS: Specific recruitment ofimmunocompetent cells by transfer factor, in Lawrence HS, and Bandy M, Editors: Mediators of cellular immunity, New York, 1969, Academic Press, Inc., p. 143. 6. Cooper MD, Chase HP, Lowman JT, Krivit W, and Good RA: Wiskott-Aldricb syndrome, an immunologic deftciency disease involving the afferent limb of immunity, Am J Med 44:499, 1968. 7. Oppenheim J J, Blaese RM, and Waldmann TA: Defective lymphocyte transformation and delayed hypersensitivity in Wiskott-Aldrich syndrome, J Immunol, 104: 835, 1970. 8. Spitler LE, Levin AS, Stites DP, Fudenberg HH, Pirofsky B, August C S, Stiehm ER, Hitzig WH, and Gatti R: The Wiskott-Aldrich syndrome, results of transfer factor therapy, J Clin Invest 51:3216, 1972. 9. Baldini, MG: Nature of the platelet defect in the WiskottAldrich syndrome, Ann N Y Acad Sci 201:437, 1972. 10. Krivit W, and Good RA: Aldrich's syndrome (thrombocytopenia, eczema and infection in infants), Am J Dis Child 97:137, 1959.

WITHIN the past decade, the use of electronic methods has laid bare much of the mechanism underlying the myotatic, or stretch, reflex of mammalian striated muscle. Outstanding among these advances are Lloyd's demonstration of the monosynaptic nature of the myotatic reflex pathway, and his disclosure that fibres of large diameter (Group I fibres) constitute the afferent limb of this reflex arc1. However, the specific receptor organ responsible for initiating the stretch reflex has so far eluded positive identification, though the balance of evidence suggests muscle spindles rather than Golgi tendon organs2.

It should delight dermatologists, extraordinary morphologists, that the cell is still central to understanding disease and normal function and that there are still cells in the skin without well-defined function. All are familiar with the Langerhans' cell, which is the antigen-presenting cell in the epidermis and part of the important afferent limb of the immune system. Two cells are standing in the wings, the epidermal Merkel cell and the dermal veil cell, trying to make it big like the Langerhans' cell. The Merkel cell, in addition to prominent granules, a regular distribution within the basal layer and tumors, has a catchy name and has been getting good exposure in the investigative and dermatopathologic literature; it doesn't need any further publicity. I wish to concentrate on what appears to be a "shy" cell in the Garrison Keillor sense, the veil cell. (Garrison Keillor, contemporary US public radio personality hosting "A Prairie