The immunology of HIV disease and pregnancy and possible interactions.

HIV infection may impair a large portion of the human immune response. Infection of CD4+ T cells results in depletion of this population, leading to dysfunction of T-cell-dependent activities. Numerous other immune functions are directly or indirectly impaired, including the function of CD8+ T cells and decreases in total lymphocytes, IL-2 secretion, IL-2R expression, proliferative response to mitogens, NK activity, ADCC, and several other measures. Immune alterations seen in normal pregnancy include decreases in CD4 and T cells, the proliferative response to mitogen, IL-2 secretion, and NK activity. These changes are largely cellular and usually are not apparent clinically. Normal pregnant women are immunocompetent. When pregnancy is complicated by asymptomatic HIV infection, the obstetric outcome does not seem to be adversely affected. Preliminary studies show that the course of HIV disease may not be adversely affected in these women, but this matter is the subject of intense investigation.

Immunology of HIV and pregnancy. The effects of each on the other.

Infection with HIV may significantly affect the human immune response. Depletion of CD4 T cells directly or indirectly results in global immune dysfunction, including both cellular and humoral components of the immune system. Ongoing viral replication leads to progressive immune destruction despite apparent clinical latency. The end result, if left untreated, is CD4 T-cell depletion, severe immune compromise, opportunistic infection, and eventual death. Pregnancy has been purported to induce an altered immune state to protect the fetus from immune rejection that may leave the mother with impaired immunity. This theoretical risk has been overemphasized, and, in fact, only limited data suggest that certain infections may have worse presentations and outcomes during pregnancy. The mother maintains immunocompetence throughout gestation and is not overwhelmed with opportunistic infection. Women infected with HIV may experience some decline in CD4 T-cell percentages and possibly in function. It is not clear whether any of the effects will significantly affect long-term outcome. Infection with HIV may predispose pregnant women to a variety of adverse pregnancy outcomes, including preterm labor, prematurity, low-birth-weight infants, postpartum endometritis, and other infectious morbidity. Larger controlled studies are necessary to determine the frequency of these adverse outcomes and whether they will predominantly affect the severely immunocompromised HIV-infected pregnant women.

Hypoplasia of the trachea in dogs: 103 cases (1974-1990).

A multi-institutional retrospective study of 103 dogs in which hypoplasia of the trachea was diagnosed was conducted. Bulldogs (55%) and Boston Terriers (15%) were most commonly affected. Age at diagnosis ranged from 2 days to 12 years, with a median of 5 months. Hypoplasia of the trachea was diagnosed more frequently in males (66%) than females (34%). Congenital anomalies in dogs with hypoplasia of the trachea included elongated soft palate (n = 44), stenotic nares (n = 23), cardiac defects (n = 12), and megaesophagus (n = 10). Ratios between tracheal lumen diameter and depth of the thoracic inlet or width of the third rib did not correlate with dyspnea. Of 42 dogs reexamined greater than 6 months after diagnosis, 25 (60%) were clinically normal. The remaining 17 were dyspneic and 15 (88%) had concurrent respiratory or cardiovascular disease that could account for their clinical signs. Hypoplasia of the trachea appears to be tolerated well in the absence of concurrent respiratory or cardiovascular disease.

Comparison of french-pezzar and Malecot catheters for percutaneously placed gastrostomy tubes in cats.

Gastrostomy tubes were placed percutaneously in 28 cats by use of an endoscope. French-pezzar mushroom-tip catheters were used for 14 of the procedures, and Malecot catheters were used for the remainder. Inner flanges were not used in gastrostomy tube placement. The french-pezzar catheters remained in place and functional for 2 weeks in all 14 cats. The Malecot catheters remained in place and functional for 2 weeks in 4 cats. Malecot catheters pulled out in 10 cats, and 2 of these cats died or were euthanatized because of complications. The gastrostomy tubes were removed in 18 cats 2 weeks after placement by applying gentle, steady traction and removing the entire catheter or by cutting the tube flush with the skin and leaving the catheter tip in the cat's stomach. Neither method of removal was associated with problems.

The use of the laryngeal mask airway in day case and short stay surgery.

An increase in day case surgery has followed a reduction in the number of hospital beds available. Anaesthetic methods and techniques must be modified so that patients can be safely discharged as soon as possible following surgery. The use of Brain's laryngeal mask airway (L.M.A.) can play a part in achieving this objective.

A clinical evaluation of the marginal adaptation of porcelain laminate veneers.

This paper reports the findings of a short-term (12 month) study to assess the initial adequacy and subsequent changes in the marginal adaptation of a series of porcelain laminate veneers (PLVs) placed in a highly selected group of patients by a single operator under strictly controlled conditions. The findings together with those of retrospective scanning electron microscope assessments of replicas of the veneered teeth indicate that ideal marginal adaptation is difficult to achieve when placing PLVs and that imperfections in the marginal adaptation of recently placed PLVs could be future sites for staining and caries in clinical service. It is suggested that, in prescribing PLVs, clinicians should take account of the limitations of such restorations.

Depression kinetics of ornithine transcarbamylase in Escherichia coli.

A mathematical model for the derepression of ornithine transcarbamylase (OTC) in Escherichia coli strain W was derived from a set of 14 assumptions concerning the arginine regulon. The model assumes that active repressor for the arginine regulon is unstable and is only formed when the level of arginyl-tRNA is in excess of the level necessary to maintain protein synthesis for a given cell doubling time. The presence of active repressor was assumed to inhibit the synthesis of messenger RNA coding for the synthesis of the enzymes of the arginine biosynthetic pathway. Numerical estimates of the model's parameters were made and, by simulation on a digital computer, the model was shown to fit kinetic data for derepression of OTC in E. coli W cells in minimal medium growing in flask culture with a doubling time of 60 min and growing in a chemostat with a generation time of 460 min for an assumed OTC-specific mRNA half-life (t(1/2)) of 9 min. The model was also shown to predict the increase in the size of bursts of OTC synthesis elicited by addition of arginine to cultures of derepressing E. coli cells with the increase in the delay time before arginine addition. Approximate analytical solutions to the model were obtained for the early phase of derepression and for repression of OTC. These were used to derive graphical methods for determining t(1/2) from repression and derepression transient changes in the OTC level.

Reflex sympathetic dystrophy in a dog.

Reflex sympathetic dystrophy is a well-recognized syndrome in human patients following injury to an extremity. The syndrome may include hyperesthesia and autonomic changes. The autonomic changes are initial vasodilatation followed by vasoconstriction (e.g., edema followed by cyanosis, and cool skin); hyper- or hypohydrosis; atrophic changes in the skin, subcutis, and muscles; and osteoporosis. Early treatment with a short course of steroids and infiltration of the painful site with lidocaine may alleviate symptoms. If that fails, sympathetic ganglionic block with lidocaine (and possibly steroids) or surgical sympathectomy may provide resolution. A case of reflex sympathetic dystrophy in a dog is presented, involving bilateral distal hind-limb edema and hyperesthesia.

Teeth grinding, tongue and lip biting in a 24-month-old boy with meningococcal septicaemia. Report of a case.

This paper describes the management of a 24-month-old boy who presented with self-inflicted trauma to his lower lip and tongue, and teeth grinding, 21 days after developing meningococcal septicaemia. A decision to observe and prescribe palliative therapy was made. Extraction of the lower right deciduous canine, which had become non-vital, possibly due to bruxism, was carried out.

Clinical and pathologic effects of a modified technique for application of spiral prostheses to the cervical trachea of dogs.

A modified surgical technique for application of extraluminal polypropylene spiral prostheses (PSP) to the trachea was developed. A portion of the segmental blood supply to the collapsed segment of trachea was maintained by fenestrating rather than completely dissecting the right lateral pedicle. Polypropylene spiral prostheses were applied to the cervical trachea of 12 dogs (group I) via the modified technique and to 12 dogs (group II) with the identical surgical dissection but without PSP applied. Clinical abnormalities included mild coughing in group I dogs and swelling of the incisions in both groups. Limited necrosis and moderate degeneration and inflammation were observed histologically in both groups. Pathologic changes were worse in the caudal cervical segment of the trachea. Mucosal regeneration was present on day 10 in both groups. Transmural tracheal necrosis was not observed. The modified technique for application of PSP is recommended by the authors because it provides adequate surgical exposure and the blood supply preserved by segmentally dissecting the right lateral pedicle is adequate to maintain tracheal viability.

Inhibition by propranolol of bile acid- and PGE1-stimulated camp and intestinal secretion.

Three colonic and three ileal loops were prepared in six rabbits pretreated with propranolol (PR) 4 mg./kg. I.V. and in five untreated rabbits. In random order, 1 ml. of either deoxycholic acid (DCA) 6 mM., prostaglandin E1 (PGE1) 20 microgram./ml., or saline was placed in each colonic loop and 1 ml. of either cholera enterotoxin (CE) 10 microgram./ml., PGE1 20 microgram./ml., or saline was placed in each ileal loop. In untreated animals, DCA and PGE1 in the colon and CE and PGE1 in the ileum stimulated (P less than 0.01) adenylate cyclase (AC) and net secretion. In the colon, PR abolished DCA-stimulation of AC and net secretion and decreased PGE1-stimulated AC (P less than 0.01) and net secretion. In conclusion, at the doses and times studied, colonic-AC and net secretion stimulated by PGE1 or DCA was distinguished from small bowel-AC and net secretion stimulated by PGE1 or CE.