Parasacrococcygeal approach for the resection of retrorectal developmental cysts

Congenital developmental cysts are the most common retrorectal tumors. Five adult patients, two men and three women, with congenital developmental cysts were operated on via a posterolateral approach through a parasacrococcygeal incision. All wounds healed primarily with no infection or other complications. Recurrent perianal infections and repeated anorectal operations suggest the possibility of retrorectal growths; thus diagnosis requires physician awareness. Computerized tomography is the best preoperative diagnostic test to delineate anatomy and to rule out bony involvement. Because of an infection rate of approximately 30 percent, as well as the presence of symptoms and malignancy in 8 percent of the patients, surgical excision is the treatment of choice. The authors use a posterolateral approach that provides excellent exposure and obviates the need for removal of the coccyx or transection of the sphincter muscle. The authors believe this to be the procedure of choice for excision of retrorectal cystic lesions.

A17: a broad-field amacrine cell in the rod system of the cat retina

A17 amacrine cells of the cat retina have been penetrated with horseradish peroxidase (HRP)-filled microelectrodes and their light responses recorded. These cells depolarize in sustained fashion to steps of light. Viewed in retinal wholemounts, HRP-injected cells have a spokelike radiating splay of very fine dendrites (0.1 micron diam) passing diffusely through all strata of the inner plexiform layer (IPL) to run primarily in strata 4 and 5. There are as many as 1,000 large, regularly spaced beads borne on the 500- to 1,200-micron diameter dendritic field. Cell body sizes range from 9 to 13 micron. In the electron microscope, the dendritic beads in sublamina b of the IPL are seen to synapse reciprocally with rod bipolar axon terminals. Dendritic beads in sublamina a rarely make synapses, but between the beads in this layer, input from at least three distinctive amacrine profiles occurs. Though diffuse at the light microscopic level, A17 thus appears to be structurally bistratified, with amacrine input in sublamina a and bipolar input in sublamina b. It is likely that A17 can be identified with AI. A17 signals are driven almost exclusively by rods. The spectral sensitivity peaks at 507 nm, identical with that of pigment epithelial cells. Light adaptation abolishes all but a small hyperpolarizing component of the signal. The overall intensity-response range is similar to that of AII amacrine cells. When receptive fields of A17 cells are mapped with slit stimuli, a broad, single-component curve is measured approximately covering the dendritic field. The receptive field is well described by a linear electrical model with a mean space constant of 259 +/- 97 micron (SD). On the other hand, responses to centered slit stimuli of varying width yielded space constants of only 38 +/- 29 micron. A17 amacrines are thus broad-field components of the cat's rod system but with very little capacity for spatial integration. Receptive-field measurements are not supportive of the notion of isolated dendritic regions.

Genetic brain polypeptide variants in inbred mice and in mouse strains with high and low sensitivity to alcohol

Twelve genetically determined brain polypeptide charge variants were identified by comparing cerebellar vermis of 7 inbred mouse strains and of mice selectively bred from 8 strains closely related to these 7 ancestral strains and one other for acute behavioral sensitivity to the sedative effects of ethanol. The selectively bred ethanol-sensitive (LS, long sleep) and insensitive (SS, short sleep) mice exhibited different allelic variants at 6 of these 12 gene loci expressed in the cerebellum. Variant polypeptide A1 (81 kdalton, pI 5.6) was shown to be associated with the membrane of synaptosomal mitochondria and to exhibit a basic variant in SS mice that is determined by a dominant allele. Other variant polypeptides showed codominant inheritance in F1 crosses. However, the phenotype of no single one of these brain polypeptides consistently correlated with the ethanol behavioral sensitivity of the 7 inbred mouse strains nor of 8 recombinant inbred (B X D, C57BL X DBA) strains. This finding supports the hypothesis that a substantial amount of inbreeding, leading to random fixation of alleles independent of selection for ethanol sensitivity, occurred during the breeding of the SS and LS mice. The present findings of a lack of a strong association between sleep time and a brain polypeptide variant do not preclude the existence of a major gene effect contributing to variation in acute sensitivity to ethanol but are consistent with reports that multiple loci are responsible for the difference in ethanol sensitivity between SS and LS mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Low-dose dopamine preserves renal blood flow in endotoxin shocked dogs treated with ibuprofen

Drugs that inhibit prostaglandin (PG) biosynthesis improve hemodynamics and survival in experimental endotoxic and septic shock. The therapeutic utility of these agents in the management of septic patients may be limited, however, by their tendency to decrease renal blood flow (RBF) in animals and humans stressed by experimental manipulations or disease states that promote renal vasoconstriction. In the present study, we addressed this question: can low-dose intravenous (iv) dopamine (4 micrograms/kg/min), a known renal vasodilator, improve renal perfusion in endotoxin-shocked dogs treated with the PG synthesis inhibitor, ibuprofen. RBF was measured in pentobarbital anesthetized dogs using an electromagnetic flow meter. After obtaining baseline hemodynamics, Escherichia coli endotoxin (1.5 mg/kg) was given iv. The dogs were randomized 30 min later into three groups: Group I received saline; Group II received ibuprofen (12.5 mg/kg, iv); Group III received ibuprofen plus dopamine. Comparison of Groups I and II revealed that ibuprofen increased mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P less than 0.0001 and P = 0.002, respectively) and decreased RBF (P = 0.019). Adding low-dose dopamine (Group II vs Group III) did not significantly affect MAP or SVR, but did augment RBF (P less than 0.001). We conclude that low-dose dopamine improves renal hemodynamics in ibuprofen-treated endotoxemic dogs.

Partial deletion of distal 17q

A newborn female was found to have a deletion of the terminal portion of 17q. Prominent manifestations included microcephaly, apparent hypertelorism, epicanthic folds, a broad nasal bridge with anteverted nostrils, posteriorly angulated ears, micrognathia, widely spaced nipples, arachnodactyly with proximal thumbs, and a coxa vara deformity. The unbalanced translocation was inherited from the mother, who had a reciprocal translocation involving the terminal portions of 2p and 17q. To the best of our knowledge, this is the first report of a liveborn infant with deletion of the distal portion of 17q with the exception of reports of patients with ring chromosome 17.

A new tube for simultaneous gastric decompression and jejunal alimentation

A new tube has been devised for simultaneous gastric decompression and jejunal enteral alimentation. The tube is inserted by the nasogastric route intraoperatively. What differentiates this from earlier tubes is the addition of two inflatable balloons that facilitate passage of the tip of the tube through the retroperitoneal duodenum and into the proximal jejunum. Such a device is needed because the advantages of enteral alimentation in the postoperative patient include safety, low cost and significant metabolic benefits.

Intestinal permeability changes and excretion of micro-organisms in stools of infants with diarrhoea and vomiting

The relation between diarrhoea and vomiting, the excretion of stool micro-organisms, and the passive intestinal permeability in 20 infants living in a deprived urban area was studied prospectively from birth to age 6 months. Intestinal permeability was measured from the ratio of lactulose to mannitol recovered in the urine of infants receiving feeds containing both markers. Micro-organism excretion was found to occur in both the presence and absence of gastrointestinal symptoms, but a significantly higher mean intestinal permeability was recorded in those infants with symptoms and organisms in the stool than in those with neither. An increased intestinal permeability may be a sign of mucosal damage by intestinal micro-organisms.

Embryology of the middle third of the face

This article compares the midface appearance of two histological sections, one an embryo at the 6 mm stage of development and another at the 28 mm stage. It demonstrates the considerable cellular differentiation and development that takes place, and suggests that this area is liable to anomalies if the rapid, sequential and considerable amount of growth in this area is disturbed by inherited or environmental factors.

Dopamine-containing amacrine cells of rhesus monkey retina parallel rods in spatial distribution

Dopamine-containing amacrine cells of rhesus monkey were found everywhere outside of the foveola in whole, flat retinas by the formaldehyde-glutaraldehyde fluorescent method. There were about 7500 such cells in a single retina and their density, determined by cell counts and measured by a nearest neighbor method, was minimal in foveal and peripheral regions and maximal at 3 mm from the center of the fovea. Compared to density distributions of other retinal neuron types, dopamine-containing amacrine cells correlated only with rods, which also had a peak density at 3 mm eccentricity. Cones and ganglion cells peaked in the foveal pit, or within 1 mm of it, respectively. As the distribution of dopamine-containing cells followed that of rods, it is suggested that dopamine could be involved in the rod neuronal circuitry of primates.

Interstitial nucleus of Cajal (INC) projections to the region of Probst's tract

These studies were designed to investigate projections of the interstitial nucleus of Cajal (INC) to the region of the contralateral Probst's tract (PrTr). In electrophysiological experiments, INC neurons were antidromically activated from the contralateral PrTr, the medial longitudinal fasciculus (MLF) at medullary levels and the MLF at spinal cord levels. Some INC cells could be antidromically activated only from PrTr and others from both PrTr and the MLF. Anatomical experiments confirmed the existence of an INC projection into the region of the contralateral PrTr. Following injections of fluorescent dyes into the PrTr area, retrogradely labeled neurons were observed in the contralateral INC, with only occasional labeling ipsilaterally. Injections which included the medial vestibular nucleus labeled a greater number of INC cells ipsilaterally. After injections of dyes into the medullary MLF, retrogradely labeled cells were observed bilaterally in INC, although in greater numbers ipsilaterally. In experiments in which different dyes were injected into PrTr and the MLF, double labeled cells were found in the contralateral INC.

Positive direct antiglobulin tests and immune hemolytic anemia in patients receiving procainamide

To characterize the autoimmune phenomena in patients receiving procainamide, we studied the prevalence of positive direct antiglobulin (Coombs') tests and immune hemolytic anemia in 100 such patients and compared them with 100 age-matched and sex-matched controls. There was a significant increase in the frequency of positive direct antiglobulin tests in patients receiving procainamide (21 vs. 10 per cent, P = 0.05). The mechanism of red-cell sensitization in patients receiving procainamide was the production of red-cell autoantibody, which was serologically indistinguishable from that seen in warm autoimmune hemolytic anemia. In contrast, positive direct antiglobulin tests in control patients were due to the presence of complement components. Red-cell autoantibody production secondary to procainamide was not correlated with a higher-than-expected frequency of antinuclear antibodies or the clinical syndrome of drug-induced lupus erythematosus. In the series of 100 patients receiving procainamide, we identified three cases of immune hemolytic anemia. In two of the three cases, the anemia resolved after the medication was discontinued and did not require steroid therapy. We conclude that procainamide often results in the production of red-cell autoimmune phenomena.

Intestinal permeability in the newborn

Passive intestinal permeability in 33 newborn babies was studied using feeds containing lactulose and mannitol. Each marker is thought to pass across the gut wall by a different route; lactulose by a paracellular and mannitol by a transcellular pathway. Neither is metabolised and both are wholly and solely excreted by the kidney; urinary recovery is a measure of the intestinal uptake. Babies born before 34 weeks' gestation exhibited a higher intestinal permeability to lactulose than more mature babies, and all preterm babies showed an appreciable decline in lactulose absorption during the first week of oral feeds. Babies of 34 to 37 weeks' gestation achieved a 'mature' intestinal permeability to lactulose within four days of starting oral feeds. These findings may reflect the immaturity of the gut of the preterm baby rather than a process essential to adaptation to enteral nutrition.

Enhanced intestinal permeability in preterm babies with bloody stools

During a study of the intestinal permeability of newborn babies, three exhibited a sudden increase in lactulose absorption in association with the passage of bloody stools. An enhanced intestinal permeability may be an expression of the disruption of mucosal integrity in necrotising enterocolitis.

The association of extrahepatic bile duct atresia and neonatal Epstein-Barr virus infection

An infant with uncorrectable extrahepatic bile duct atresia was found to have evidence of Epstein-Barr virus infection during the neonatal period. It is probable that the infection was acquired in utero. In view of the association of hepatitis with the Epstein-Barr virus in later life, it is possible that this infection was responsible for the development of bile duct obstruction.

Amacrine cells in scotopic vision

Signals from rod bipolar cells of cat retina are processed by a variety of rod amacrine cells before finally arriving at ganglion cells. Three of these rod amacrine cells (AII, A13, and A17 ) have been studied at the physiological and anatomical levels; the results suggest that each carries out a unique visual function: AII cells appear to quicken the response time of the rod system in the mid-scotopic range, while A17 cells may increase the light-gathering area of rod bipolars near visual threshold. Stimulation of A13 cells may disinhibit ganglion cells, thus heightening their responsiveness at low levels of illumination.

York Mason procedure for repair of postoperative rectoprostatic urethral fistula

Rectoprostatic fistula is a rare complication after transurethral resection of the prostate or prostatectomy for benign and malignant neoplasms of the prostate. Repair of these fistulas is difficult, especially when previous treatment includes radiation therapy to the prostate. Various operative approaches have been described to close these inaccessible fistulas. Because of their location near the outlet of the pelvis, access to or exposure of these fistulas is quite limited. These fistulas can be easily exposed and repaired through the posterior wall of the rectum (transsphincteric approach). Three patients with rectoprostatic urethral fistulas were repaired successfully by using this method.

Measurement of tracheal mucous transport rate in the horse

Tracheal mucous transport rates were measured in 12 nonanesthetized horses after an intratracheal injection of 99mtechnetium-sulfur colloid. The transport rate of the subsequent bolus of radioactivity was determined, using a portable scaler rate meter fitted with a high-energy gamma-scintillation probe. A gamma-scintillation camera was used to verify bolus form and movement in 1 horse. The mean tracheal mucous transport rate was 1.66 +/- 0.24 cm/min.

Sex ratio and heterozygote advantage in cystic fibrosis families

The families of aunts and uncles of cystic fibrosis (CF) patients were compared with one another and with controls in order to test claims of increased fertility and sex ratio in families containing the CF allele and to identify the more fertile sex. Uncles' families were found to contain a significant excess of sons, particularly at primiparous births, as well as a significantly increased sex ratio. Reanalysis of published records of CF sibships confirmed the effect of parity on sex ratio. The families of uncles were also exceptional in exceeding the size intended, although their mean size was not raised significantly. It is suggested that these effects could be related to an interaction between CF-related, paternally-derived antigens and the maternal immune system.