Changes in CSF pressure after mannitol in patients with and without elevated CSF pressure

In view of the current concern that rapid infusion of mannitol might initially aggravate intracranial hypertension, the effects of a mannitol infusion on lumbar cerebrospinal fluid pressure (CSFP) were investigated in 49 patients. The studies were performed when the patients were under general anesthesia prior to elective craniotomy for tumor resection or intracerebral aneurysm clipping. The patients were divided into two groups: 24 patients with normal CSFP (Group I, mean CSFP 10.5 mm Hg) and 25 with raised CSFP (Group II, mean CSFP 20.8 mm Hg). Measurements of CSFP, mean arterial blood pressure (MABP), and central venous pressure (CVP) were made serially during and after the infusion of 20% mannitol (1 gm.kg-1 infused over a 10-minute interval). In both groups, mannitol infusion provoked a fall in MABP and an increase in CVP. An immediate decrease [corrected] in CSFP was observed in Group II, whereas CSFP increased transiently but significantly in Group I. Analysis of the arterial and venous driving pressures which contribute to CSFP suggests that the transient increase in CSFP after mannitol in Group I was partly due to the increase in CVP. The presence of intracranial hypertension may thus alter the CSFP response to arterial and venous pressure changes. Cerebral blood volume (CBV) was measured in dogs in a separate study analogous to the human protocol. The CBV increased approximately 25% over control values after mannitol infusion both in the normal animals and in those with CSFP raised by an epidural balloon. The response of the CSFP to mannitol infusion differed between both groups in a fashion similar to that observed in the human subjects. Thus, differences in CBV changes after mannitol do not account for the difference in CSFP response between normal subjects and those with raised CSFP.

Permeability of the rat small intestine to carbohydrate probe molecules

1. Absorption of carbohydrate probe molecules from ligated loops of rat small intestine was studied. Absorption was determined by measuring recovery of molecules in the urine, corrected for incomplete recovery after intravenous injection, and was examined for correlation with several parameters of molecular dimension. 2. Absorption depended on molecular volume rather than relative molecular mass, molecular radius or molecular area. 3. Molecules with a molecular volume below 225 X 10(-3) nm3 were absorbed to a greater extent than larger molecules, and absorption was affected critically by molecular volume, small changes in volume producing considerable variation in absorption. 4. Absorption of larger molecules was not affected by changes in volume within the range 362 X 10(-3)-1128 X 10(-3) nm3. 5. These findings support the concept that there are at least two aqueous diffusion pathways across the intestinal mucosa. small molecules diffusing through a small channel of finite dimension, compatible with a transcellular aqueous pore, whilst large molecules diffuse through a less frequent pathway of considerably larger dimensions.

A physiological approach to surgery for acute rupture of the papillary muscle

There is controversy regarding the optimal management of patients in whom acute papillary muscle rupture develops. This study evaluates the effect of division of the anterolateral papillary muscle on left ventricular (LV) function and compares two methods of treatment--mitral valve replacement (MVR) and mitral valve repair. Thirteen pigs were placed on cardiopulmonary bypass, and interventions were performed in an isolated beating heart preparation. LV function was assessed with a compliant intraventricular balloon at baseline, after division of the anterolateral papillary muscle (Divided), after repair of the divided papillary muscle (Repair), and finally after MVR. Division of the anterolateral papillary muscle caused a significant deterioration in LV function. Function was maintained at this level after mitral valve repair but deteriorated with MVR. Developed pressure measured at baseline was 179 +/- 13 mm Hg; Divided, 148 +/- 11 mm Hg (p less than 0.05 versus baseline); Repair, 149 +/- 15 mm Hg; and MVR, 95 +/- 8 mm Hg (p less than 0.05 versus Divided) at a balloon volume of 20 ml. These results suggest that LV function is impaired by papillary muscle rupture. Repair of the ruptured papillary muscle is associated with better LV function than is MVR.

Microbiological Quality of Crabmeat During Processing

Duplicate samples of crab and crabmeat (body meat and claw meat) were collected four times a day for two consecutive days at seven in-line locations (plus finished product claw and body meat) along the processing lines of 47 crabmeat plants located along the Atlantic Ocean and Gulf of Mexico coasts of the United States. All the plants adhered to Good Manufacturing Practice, as determined by visual inspection. Two sanitation inspections and sample collections were conducted at 5-month intervals to reflect seasonal variation. In all, 8,477 in-line samples and 2,459 finished product units of blue crab and crabmeat and 522 in-line samples and 128 finished product units of red crab and Maine crab and crabmeat were analyzed microbiologically. Geometric mean aerobic plate count at 35°C (APC 35) values increased from 1,200 CFU/g before pick to 20,000 CFU/g in the finished product (body meat). For claw meat, APC 35 values increased from 15,000 CFU/g before pick to 24,000 CFU/g in the finished product. Aerobic plate count at 30°C (APC 30) values were consistently higher (2-fold or less) than APC 35 values. Coliform counts in both finished products were ≥19/g in approximately 60% of the units. Coliforms exceeded 500/g in 3.8 and 3.2% of the finished product units for body meat and claw meat, respectively. Geometric mean Escherichia coli counts were <3 for all sample sites and finished products, with only 3.3 and 2.7% of the units showing detectable E. coli for body meat and claw meat, respectively. Geometric mean values for Staphylococcus aureus were 16.8/g for finished body meat and 16.0/g for finished claw meat; approximately 20% of the units of both finished products had S. aureus values >100/g. S. aureus counts increased significantly after picking.

Antibody responses to toxic-shock-syndrome (TSS) toxin by patients with TSS and by healthy staphylococcal carriers

Serum samples taken from women with toxic-shock syndrome (TSS) and from women without a history of TSS were examined for the presence of antibodies to toxic-shock-syndrome toxin (TST). Serum samples from 38 women with TSS and from 70 women with no history of TSS were analyzed by radioimmunoassay (RIA) and by an enzyme-linked immunoadsorbent assay (ELISA). Antitoxin titers obtained by the assays were highly correlated. Antibody levels in sera of women with TSS, or a history of TSS, were significantly lower than levels in sera of women with no prior evidence of TSS. The mean level of antitoxin titers in the total sample of acute, convalescent, and recovered TSS groups was significantly lower than that of the control groups, which consisted of 31 carriers of genital Staphylococcus aureus and a similar number of age- and race-matched noncarriers. Although a trend toward elevated antitoxin titers was apparent after recovery, no vigorous immunologic response to TST was noted. In contrast, the majority of healthy women demonstrated measurable antitoxin titers, a finding indicative of current or prior colonization with TST-producing strains of S. aureus. The data suggest that absence of antibodies to the TSS toxin may be a predisposing factor in the development of clinical disease.

Antagonism of pancuronium in renal failure: no recurarization

Neuromuscular transmission was measured using train-of-four stimulation, during and after anaesthesia, in 20 patients with end-stage renal failure. Neuromuscular blockade was provided with pancuronium in single doses of either 3 or 6 mg per 70 kg, and antagonized at 10% recovery with atropine and neostigmine 2.5 mg per 70 kg. Reversal was followed by progressive recovery of muscle twitch in every patient during the 3 h of the study. Recovery was more rapid after the smaller dose of pancuronium and was inversely correlated with the duration of blockade. It is concluded that, when pancuronium is antagonized with neostigmine in patients with renal failure, neuromuscular transmission recovers without evidence of recurarization. However, when large doses of pancuronium are antagonized with neostigmine 2.5 mg, recovery may be insufficient to ensure normal ventilatory function.

A patterned macular dystrophy with yellow plaques and atrophic changes

Three middle-aged male patients are described with a peculiar patterned dystrophy of the macula. The basic lesions are discrete yellow plaques typically confined to the macular area and radiating from the fovea. They appear to be located at the level of the retinal pigment epithelium (RPE). With the passage of time some of the yellow plaques altered in extent and configuration, and atrophic changes appeared or extended. Visual acuity and electrophysiological tests are either normal or only moderately affected. The lesions appear to be distinct from the patterned dystrophies of the retina already described and from other conditions characterised by yellow or white deposits at the level of the RPE.

In vivo suppression and enhancement of the murine homocytotropic antibody response by staphylococcal enterotoxin A

Effects of staphylococcal enterotoxin A (SEA) on the mouse homocytotropic antibody (HCA) system were studied. Groups of BDF mice received 10 micrograms SEA either orally or intraperitoneally at 0, 24, 48 h before or after immunization with 100 micrograms ovalbumin in 1 mg A1(OH)3 gel. Primary and secondary HCA responses were determined by 48-hour passive cutaneous anaphylactic reactions in genetically hairless mice. It was found that effects of SEA on HCA responses were dependent on the time and route of SEA administration. In general, early administration (48 h before immunization) of SEA showed suppression, while later administration (either 24 h before or after immunization) of SEA demonstrated enhancement. A further delay of SEA administration (48 h after immunization) exerted suppressive effects except when it was given intraperitoneally in the anamnestic HCA experiments. The mouse HCA system proved to be a suitable in vivo correlate of in vitro plaque-forming cell responses modulated by SEA.

Effects of papaverine on the retinal microcirculation

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