High prevalence of adenomatous polyps of the duodenal papilla in familial adenomatous polyposis

Eighteen consecutive asymptomatic patients with familial adenomatous polyposis (both familial polyposis coli and Gardener's syndrome) were studied over a 12-month period; side-viewing upper endoscopy and biopsy were used to assess the frequency of adenomatous polyps of the duodenal papilla. Nine of the 18 patients demonstrated adenomatous polyps of the papilla, varying in size and appearance from microadenomas in normal-appearing duodenal papillae (two) to a sessile polyp 3 cm in diameter. Two were tubulovillous adenomas (0.5 cm and 2 cm in diameter) and the remainder were tubular adenomas. Severe atypia and malignancy were not encountered. These findings reveal that adenomas of the duodenal papilla are common in individuals with familial adenomatous polyposis. Because of these findings and because of the known risk of periampullary adenocarcinomas and nonmalignant complications of polyps of the duodenal papilla in patients with familial adenomatous polyposis, upper gastrointestinal screening of such patients should include examination of the duodenal papilla with a side-viewing endoscope.

High-altitude mountaineering and brain function: neuropsychological testing of members of a Mount Everest expedition

Concern has been raised regarding the possibility that hypoxic conditions encountered during high-altitude mountaineering may have lasting harmful effects on the human brain. Members of an expedition to Mount Everest completed a series of neuropsychological tests before and after the expedition. Exposure to altitudes above 7,200 m was limited to a maximum of four consecutive nights, separated by rest periods at lower altitudes. No significant decline in performance was observed on any test. The subjects also completed a short series of tests at different altitudes during the expedition. No significant deterioration was observed at altitudes up to 7,500 m. There do not appear to be lasting harmful effects on brain function under these conditions.

Liver histology in rheumatoid arthritis patients receiving long-term methotrexate therapy. A prospective study with baseline and sequential biopsy samples

Twenty-nine patients with active rheumatoid arthritis receiving long-term oral weekly methotrexate (MTX) therapy were studied to determine the extent of their hepatic architectural changes. Liver biopsies (n = 101) were performed in all patients before the initiation of MTX therapy, after 2 years, and annually thereafter (mean duration of therapy 53 months). The hepatic histologic grade (5-point scale) in 25 patients increased (worsened) (mean +/- SEM change 0.84 +/- 1.02; P = 0.001). Fibrosis, confirmed by trichrome staining, developed in 14 of 27 patients (52%). A history of alcohol consumption prior to starting MTX correlated significantly with subsequent worsening of the liver biopsy grade (r = 0.55, P = 0.0054). Alcohol intake prior to study entry, elevated weight at MTX initiation, and dose and duration of MTX were significantly associated with the development of fibrosis. Elevations in serum aspartate aminotransferase levels at 29-53 months of therapy correlated with the increase in hepatic histologic grade at the 3-year biopsy (r = 0.50, P = 0.04) and 4-year biopsy (r = 0.58, P = 0.03). We conclude that long-term MTX therapy in rheumatoid arthritis patients results in a statistically significant worsening in hepatic histologic grade, with common development of mild fibrosis. We do not consider these changes to be clinically significant at present.

Backward masking, information processing, and schizophrenia

Many researchers have used backward masking to examine information-processing speed in schizophrenic subjects. The validity of this approach rests upon two main assumptions. One is that the mask effectively limits the time a previously presented stimulus is available for processing. The other is that the components of the masking mechanism in schizophrenic subjects are comparable to those in control groups. It is argued that the masking procedures used in these studies fail to meet either assumption. Alternative interpretations of these investigations, however, suggest important hypotheses for further research in our quest to understand information-processing deficits associated with schizophrenia.

Pathophysiology of rigidity and akinesia in Parkinson's disease

Although rigidity and akinesia are two of the cardinal features of Parkinson's disease, their exact pathophysiology remains uncertain. Mechanisms which may contribute to rigidity include accentuation of the long-latency component of the stretch reflex and enhanced fusimotor drive causing increased sensitivity of muscle spindles. Current evidence concerning the role of these factors in rigidity is reviewed. The relationship between akinesia, prolonged reaction times, and delay in initiation of internally generated movements in parkinsonian patients is discussed.

Quantitation of colonic injury from argon laser, neodymium: YAG laser and monopolar electrocautery applied to flat mucosa and small sessile polyps of the canine colon

This study determined the optimum laser energy for ablation of colonic mucosal lesions and small sessile polyps in the canine colon. Neodymium (Nd):YAG laser, argon laser, and monopolar electrocautery were applied to exposed canine colonic mucosa for various application times at various power settings. At the minimum energy level necessary to ablate mucosa, the Nd:YAG laser caused greater muscularis injury than the argon laser and monopolar electrocautery. At higher energy levels, monopolar electrocautery and Nd:YAG laser caused greater muscularis injury than argon laser. Small surgically created polyps in the canine colon were ablated endoscopically with the three energy sources. Single-session complete polyp ablation occurred most frequently with Nd:YAG laser and least frequently with argon laser. The depth of tissue injury beneath polyp ablation sites was least with argon laser and greatest with Nd:YAG laser. This study suggests that the argon laser is safer than the Nd:YAG laser or monopolar electrocautery for coagulation of flat colonic mucosal lesions. Although the argon laser is safer for the coagulation of small sessile colonic polyps, it may be less effective than monopolar electrocautery or the Nd:YAG laser for the single-session fulguration of polyps greater than 5 mm in diameter.

Unilateral absence of the external carotid artery

We report a patient with absence of the external carotid artery. The major external branches originate from the internal carotid artery which is really a common arterial trunk. The embryology and clinical significance of this rare vascular anomaly are discussed.

Liver adenosine triphosphate and pH in fasted and well-fed mice after infusion of adenine nucleotide precursors

Nutrition is a factor which may affect the liver energy charge. Experiments were performed to determine the effect of starvation and of ATP precursors, adenine and ribose on liver energy stores. The 31P NMR spectra of well-fed and starved mice livers were studied in a perfusion system using Krebs-Henseleit buffer (KHB). The ATP precursors, adenine (20 mmol/l) and ribose (80 mmol/l), were then added to determine their effect. Their effect on the ATP dynamics during ischemia and reperfusion were then evaluated. The effects of adenine alone and ribose alone were then determined. The 31P spectra of well-fed mice demonstrated high ATP content relative to Pi, phosphoesters and phospholipids. Animals starved for 24 h showed very low ATP, high Pi and little or no detectable phospholipids. In starved animals, ATP rose steadily to approximately 50% above the baseline level when precursors were added. Pi decreased to 30% of the baseline after 40 min. Little change was noted in well-fed animals. The rate of ATP decay did not change with the onset of ischemia, whether the livers were perfused with KHB alone or KHB with precursors. Upon reperfusion, precursors improved the recovery of ATP (81% vs 49% after 20 min ischemia, 44% vs 34% after 30 min ischemia). Addition of adenine alone produced similar results, but addition of ribose alone did not significantly alter ATP recovery. In conclusion, supplying starved or post-ischemic livers with adenine or ribose and adenine does improve ATP levels.

Hepatic ultrastructure after methotrexate therapy for rheumatoid arthritis

Twenty-six patients receiving long-term oral methotrexate (MTX) therapy for rheumatoid arthritis (24 patients) or psoriasis (2 patients) were prospectively evaluated for alterations in liver morphology by light microscopy, electron microscopy, and immunofluorescence microscopy. Although only 4 MTX-treated patients had light microscopic evidence of mild fibrosis, all had evidence of collagen deposition in the space of Disse near Ito cells and changes in hepatocyte lysosomes on electron microscopy. These findings were absent from control livers. Fibrinogen, fibronectin, and type IV collagen were identified by immunofluorescence in both MTX-treated patients and controls. We conclude that long-term MTX therapy for rheumatoid arthritis is associated with alterations in hepatic ultrastructure, including collagen deposition in the space of Disse and changes in hepatocyte lysosomes.

Inactivation of biofilm bacteria

The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found by other investigators. Biofilm bacteria grown on the surfaces of granular activated carbon particles, metal coupons, or glass microscope slides were 150 to more than 3,000 times more resistant to hypochlorous acid (free chlorine, pH 7.0) than were unattached cells. In contrast, resistance of biofilm bacteria to monochloramine disinfection ranged from 2- to 100-fold more than that of unattached cells. The results suggested that, relative to inactivation of unattached bacteria, monochloramine was better able to penetrate and kill biofilm bacteria than free chlorine. For free chlorine, the data indicated that transport of the disinfectant into the biofilm was a major rate-limiting factor. Because of this phenomenon, increasing the level of free chlorine did not increase disinfection efficiency. Experiments where equal weights of disinfectants were used suggested that the greater penetrating power of monochloramine compensated for its limited disinfection activity. These studies showed that monochloramine was as effective as free chlorine for inactivation of biofilm bacteria. The research provides important insights into strategies for control of biofilm bacteria.

Common inheritance of susceptibility to colonic adenomatous polyps and associated colorectal cancers

We studied 670 persons in 34 kindreds by flexible proctosigmoidoscopic examination (60 cm) to determine how frequently colorectal adenomas and cancers result from an inherited susceptibility. Kindreds were selected through either a single person with an adenomatous polyp or a cluster of relatives with colonic cancer. The kindreds all had common colorectal cancers, not the rare inherited conditions familial polyposis coli and nonpolyposis inherited colorectal cancer. Likelihood analysis strongly supported the dominant inheritance of a susceptibility to colorectal adenomas and cancers, with a gene frequency of 19 percent. According to the most likely genetic model, adenomatous polyps and colorectal cancers occur only in genetically susceptible persons; however, the 95 percent confidence interval for this proportion was 53 to 100 percent. These results suggest that an inherited susceptibility to colonic adenomatous polyps and colorectal cancer is common and that it is responsible for the majority of colonic neoplasms observed clinically. The results also reinforce suggestions that first-degree relatives of patients with colorectal cancer should be screened for colonic tumors. This evidence of an inherited susceptibility to a cancer with well-recognized environmental risk factors supports the hypothesis that genetic and environmental factors interact in the formation and transformation of polyps.

Hepatic transplantation survival: correlation with adenine nucleotide level in donor liver

The hypothesis was tested that human donor livers with higher ATP content and energy charge achieve better results after hepatic transplantation. Biopsies were obtained from 25 donor livers immediately prior to implantation and analyzed for adenine nucleotides using high-performance liquid chromatography. The results were correlated with organ histology, transplant function and outcome. Significantly higher concentrations of ATP (4.22 +/- 2.87 vs. 0.71 +/- 0.69 nmoles per mg protein, p less than 0.01), ADP (8.75 +/- 2.96 vs. 4.49 +/- 1.95 nmoles per mg protein, p less than 0.01) and energy charge (0.43 +/- 0.15 vs. 0.21 +/- 0.04, p less than 0.02) were found in successful (n = 20) relative to failed (n = 5) livers. No significant differences were found in AMP, xanthine or hypoxanthine for the two groups, although the average values were higher in failed livers. Fifteen recipients with liver ATP concentration above 2 nmoles per mg protein and energy charge above 0.3 recovered well. Five other successful patients with lower ATP concentration (0.70 +/- 0.39 nmoles per mg protein) and energy charge (0.20 +/- 0.03) had postoperative courses complicated by infection or prolonged hyperbilirubinemia. In five patients whose livers failed, all had low ATP content and energy charge. Of these, three received a replacement liver and two died shortly after the transplantation. The study demonstrates a direct correlation between high ATP content and good posttransplant outcome.

Factors promoting survival of bacteria in chlorinated water supplies

Results of our experiments showed that the attachment of bacteria to surfaces provided the greatest increase in disinfection resistance. Attachment of unencapsulated Klebsiella pneumoniae grown in medium with high levels of nutrients to glass microscope slides afforded the microorganisms as much as a 150-fold increase in disinfection resistance. Other mechanisms which increased disinfection resistance included the age of the biofilm, bacterial encapsulation, and previous growth conditions (e.g., growth medium and growth temperature). These factors increased resistance to chlorine from 2- to 10-fold. The choice of disinfectant residual was shown to influence the type of resistance mechanism observed. Disinfection by free chlorine was affected by surfaces, age of the biofilm, encapsulation, and nutrient effects. Disinfection by monochloramine, however, was only affected by surfaces. Importantly, results showed that these resistance mechanisms were multiplicative (i.e., the resistance provided by one mechanism could be multiplied by the resistance provided by a second mechanism).

OKT3 monoclonal antibody in heart transplantation

OKT3 monoclonal antibody (OKT3) has already proved to be a valuable edition to the immunosuppression armamentarium available in cardiac transplantation. It is highly effective in treating refractory rejection, where approximately 90% of subjects may be salvaged. It may be even more valuable in prophylaxis, where in combination with an antibody suppression strategy and low-dose, "delayed" cyclosporine it appears to afford near complete protection against rejection. Moreover, OKT3-based prophylaxis seems to impact favorably on the rejection rate after the prophylaxis course has been completed. Adverse reactions are common and generally manageable, although occasional serious clinical events do occur.

Examination and characterization of distribution system biofilms

Investigations concerning the role of distribution system biofilms on water quality were conducted at a drinking water utility in New Jersey. The utility experienced long-term bacteriological problems in the distribution system, while treatment plant effluents were uniformly negative for coliform bacteria. Results of a monitoring program showed increased coliform levels as the water moved from the treatment plant through the distribution system. Increased coliform densities could not be accounted for by growth of the cells in the water column alone. Identification of coliform bacteria showed that species diversity increased as water flowed through the study area. All materials in the distribution system had high densities of heterotrophic plate count bacteria, while high levels of coliforms were detected only in iron tubercles. Coliform bacteria with the same biochemical profile were found both in distribution system biofilms and in the water column. Assimilable organic carbon determinations showed that carbon levels declined as water flowed through the study area. Maintenance of a 1.0-mg/liter free chlorine residual was insufficient to control coliform occurrences. Flushing and pigging the study area was not an effective control for coliform occurrences in that section. Because coliform bacteria growing in distribution system biofilms may mask the presence of indicator organisms resulting from a true breakdown of treatment barriers, the report recommends that efforts continue to find methods to control growth of coliform bacteria in pipeline biofilms.

Modulation of reflex and voluntary EMG activity in wrist flexors by stimulation of digital nerves in hemiplegic humans

Changes in EMG activity in the wrist flexor muscles were studied in response to electrical stimulation of digital nerves and to sudden extension perturbations at the wrist produced by a torque motor in human subjects with unilateral cerebral hemisphere lesions. With the subjects maintaining a steady voluntary contraction against a constant load, digital nerve stimulation produced a series of excitatory and inhibitory changes in tonic EMG activity from the wrist flexors in both the normal and paretic arm. The most consistent response was a period of EMG inhibition beginning approximately 38 msec after the stimulus and lasting approximately 35 msec. With relatively weak electrical stimuli, there was less EMG inhibition in the paretic arm than in the normal arm; with stronger stimuli, the inhibitory response was similar in the two arms. The electrical stimuli and mechanical perturbations were then delivered together, with the interval between them adjusted so that the expected period of inhibition following electrical stimulation coincided with either the early (M1) or the long latency (M2) components of the stretch reflex. In the normal arm electrical stimulation produced more inhibition of the M2 component than of the M1 component. In the paretic arm, inhibition during the M2 component was less marked and similar in degree to that which occurred during M1. These results are compatible with the view that M1 and M2 are normally mediated by separate neural pathways. The long latency EMG activity evoked by muscle stretch in the paretic arm of hemiplegic patients may be generated by pathways or mechanisms different from those in the intact arm.

Magnetic resonance imaging of gynecologic masses

The pelvis of 21 women with various gynecological masses were imaged with magnetic resonance (MR) imagers at 2.0 and 0.5 T. Fifteen normal individuals were used for studying the normal appearance of the female genitalia using spin echo pulse sequences with various pulse repetition (TR) and spin echo (TE) time values. Images were compared with those of the ultrasonic images, intraoperative findings, and the histopathologic examinations. The masses included simple ovarian cyst, cystadenoma, serous cystadenocarcinoma, ovarian teratoma, dysgerminoma, and uterine myoma. MR imaging was useful in demonstrating the anatomy and pathology of the cases examined in this study. It detected the internal structure of some tumors which were sonographically homogeneous. The potential of MR in staging of malignancies was demonstrated.

Nuclear magnetic resonance assessment of adenosine triphosphate (ATP) dynamics in ischemic mouse livers perfused with adenine and ribose

Hepatic energy stores are essential to liver viability. We used a mouse liver perfusion model and MR spectroscopy to study the effect of adding two precursors of ATP (adenine and ribose) on ATP dynamics during ischemia and reperfusion. Using Krebs-Henseleit buffer with or without added adenine and ribose made little difference in the ATP decay rate during ischemia, but the recovery of ATP during reperfusion was more complete when adenine and ribose were added to the buffer. These findings suggest that the addition of the precursors of ATP, adenine and ribose, to perfusate after ischemia can accelerate and enhance ATP recovery.

Physiology of the basal ganglia and pathophysiology of Parkinson's disease

This paper reviews current concepts concerning the anatomical organization and functions of the basal ganglia focusing mainly on the role of the basal ganglia in control of movement. Results of several studies which have been carried out on patients with Parkinson's disease are also reviewed and discussed as examples of altered normal physiological mechanisms.

Liver preservation for transplant. Evaluation of hepatic energy metabolism by 31P NMR

31P NMR spectroscopy proved to be an excellent, dynamic, nondestructive method for assessing the liver during cold flush and pulsatile perfusion experiments. 31P NMR spectroscopy was used to measure ATP decay, inorganic phosphate appearance, and phosphate chemical shift in the excised mouse livers subjected to cold and warm ischemia. Cold flush followed by cold preservation in saline, Krebs-Henseleit buffer, or Collins' solution showed that Collins' solution resulted in the slowest ATP decay. In temperature-controlled experiments (5 degrees -37 degrees C), ATP decay was much slower with lower temperature. In separate pulsatile perfusion experiments with oxygenated Krebs-Henseleit buffer, hepatic ATP was unchanged for at least 6 hr at 20 degrees C. At 37 degrees C, the NMR spectrum showed changes in the diphosphoesters region, but the ATP remained stable during the 6-hr perfusion. These studies suggest that for long periods of liver preservation, an adequate perfusion method should be developed.

Liver adenine nucleotide metabolism during ischemia and reperfusion of mice livers studied by phosphorous-31 nuclear magnetic resonance

Perfusion experiments were performed at 20 degrees C and 37 degrees C to study liver adenine nucleotide metabolism during ischemia and reperfusion of mouse livers using 31P NMR. Perfusing at 8 mL/min (Krebs-Henseleit buffer), ATP was shown to be stable for 6 hours. There was a progressive decrease in the phosphodiesters (glycerophosphorycholine and glycerophosphorylethanolamine) during the 6-hour period. Liver subjected to cold ischemia at 20 degrees C showed a slow decrease in the beta ATP peak during a 42 +/- 6-minute period with a rise in the inorganic phosphate accompanied by a shift of inorganic phosphate to the high field indicating intracellular acidosis. With reperfusion, the beta ATP returned to previous levels and the inorganic phosphate shifted to its original position. During warm ischemia (37 degrees C) the ATP peak disappeared within 5 +/- 1 minute and only returned to 34% of its original value after 30 minutes of ischemia, indicating damage to a certain percentage of liver cells. When the liver was subjected to multiple short periods of cold ischemia, there was complete recovery of the ATP after six cycles. Reperfusion after each period of cold ischemia resulted in an ATP recovery consistently greater than the initial amount, which gradually decreased to preischemic levels after a short period. This suggests that there is an as yet undelineated mechanism of ATP production during ischemia that attempts to protect the cell against ischemia.

Relationship between EMG patterns and kinematic properties for flexion movements at the human wrist

EMG patterns associated with voluntary wrist flexion movements were studied in normal human subjects. Initially, subjects were trained to produce movements within five specified velocity ranges while the amplitude of the movement and the opposing load remained constant. In a second set of experiments, subjects were required to produce movements at four different amplitudes, moving as rapidly as possible against a constant load. Finally, with movement velocity and amplitude kept constant, the external load was varied so that different forces were required to generate the movements. The slowest movements were associated with a prolonged burst of EMG activity from the agonist muscle with little or no antagonist activity. With increasing movement velocity, there was a gradual evolution to the characteristic "triphasic" pattern associated with rapid voluntary movements. As velocity of movement increased further, the amplitude and area of the EMG bursts increased while burst duration and interburst intervals decreased. Increases in movement amplitude were accomplished mainly by changing the timing of the EMG bursts; with larger amplitude movements the antagonist burst occurred later. With movements against larger loads there was an increase in the size of the agonist burst and a decrease in the antagonist burst, but no change in the relative timing of the EMG bursts. These systematic changes in EMG patterns associated with different types of movement provide an indirect method of obtaining information concerning the motor programs which generate the movements.

Patterns of reinnervation and motor unit recruitment in human hand muscles after complete ulnar and median nerve section and resuture

Following complete ulnar or above-elbow median nerve sections, there was no significant correlation between motor unit size (twitch amplitude) and recruitment threshold, as assessed by spike triggered averaging. This absence of orderly recruitment was attributed to misdirection of motor axons during regeneration. Following median nerve section at wrist level, where the reinnervated muscles have more synergistic actions, orderly recruitment by size appeared to be re-established. Thus, the size principle of motor unit recruitment can be re-established after nerve section in humans, if motor axons innervate their original muscles or ones with closely synergistic functions.