The effect of extraction of third molars on late lower incisor crowding: a randomized controlled trial

The problem of late mandibular incisor crowding is a well established phenomenon, the cause of which has been the substance of considerable debate over the years. A central issue is the possible role of the third molars though no definitive conclusions have been consistently drawn. This prospective study was designed to investigate the effects of randomly assigned early extraction of third molars on late crowding of the mandibular incisors. One-hundred-and-sixty-four patients entered the study from 1984 following completion of retention after orthodontic treatment. Seventy-seven patients (47%) returned for records up to a mean of 66 months later, and their start and finish study casts were digitized on a reflex microscope to determine Little's index of irregularity, intercanine width and arch length. Forty-four of the patients had been randomized to have third molars removed. There was no evidence of responder bias. Where third molars were extracted the mean increase in lower labial segment irregularity was reduced by 1.1 mm from a mean of 2.1 mm for the group where third molars were retained (P = 0.15, not statistically significant). This difference was also not considered to be clinically significant. The principal conclusion drawn from this randomized prospective study is that the removal of third molars to reduce or prevent late incisor crowding cannot be justified.

Carcinogenesis studies with the lyophilized mushroom Agaricus bisporus in mice

Continuous administration of 10, 5, and 2.5% lyophilized Agaricus bisporus (AB) mushroom in the diet of six-week-old, randomly bred Swiss mice for life induced tumors in the lungs, forestomach, glandular stomach, and ovaries in certain groups. Some of the tumor incidences were found to be statistically significant, although no dose-response relationship was established. Histopathologically, the neoplasms were classified as adenomas and adenocarcinomas of lungs, glandular stomach, and ovaries and squamous cell papillomas and carcinomas of the forestomach. AB given in both raw and baked forms induced tumors in the same species in earlier experiments. Since this fungus is consumed in lyophilized form to a certain degree in the United States, the results may carry practical significance.

Aryl radical formation during the metabolism of arylhydrazines by microsomes

Many arylhydrazines are genotoxins, although the mechanism of their genotoxicity is unknown. Previous studies have shown that arylhydrazines are metabolized to arenediazonium ions, which produce C8-arylguanine adducts in DNA suggesting the intermediacy of an aryl radical. Here we have looked for the formation of aryl radicals from arylhydrazines and microsomes by ESR spin trapping. Only hydroxyl radicals are trapped upon incubation of p-methylphenylhydrazine with rat liver microsomes and 5,5-dimethyl-1-pyrroline N-oxide (DMPO). However, hydroxyl and aryl radicals were trapped upon incubation of p-(methoxymethyl)phenylhydrazine with rat liver microsomes. Evidence for hydroperoxyl radical formation was also obtained. In contrast, when either of these substrates was incubated with microsomes from C5O cells, aryl and hydroxyl radicals were trapped. The ESR signal intensity of the spin-trapped aryl radicals parallels the extent of C8-arylguanine formation in DNA, and therefore, the aryl radical is likely the intermediate responsible for C8-arylguanine adduct formation. Aryl radicals and C8-arylguanine adducts may be related to the genotoxicity of arylhydrazines and related compounds that are oxidatively metabolized to arenediazonium ions, the precursor to aryl radicals, including arylalkyl nitrosamines, arylazo compounds, and triazenes.

Distinctive electrophysiological features of denervated muscle in uremic patients

Abnormal spontaneous activity is a hallmark of acute or subacute denervation of skeletal muscle, particularly in patients with uremic neuropathy. We report 5 patients in whom such activity was unexpectedly minimal or absent.

Outbreak of sporotrichosis among tree nursery workers

In spring 1994, an outbreak of sporotrichosis occurred at a tree nursery in Florida; 9 (14%) of 65 workers involved in production of sphagnum moss topiaries developed lymphocutaneous sporotrichosis. A cohort study of all 65 employees was conducted to identify risk factors for sporotrichosis, and an environmental investigation was done. The risk of sporotrichosis increased significantly with the duration of working with sphagnum moss (P < .05), in particular with filling topiaries (P < .05), and with having less gardening experience (P < .05). Wearing gloves was protective (P < .005). Sporothrix schenckii was cultured from patients and sphagnum moss used in topiary production. Use of restriction fragment length polymorphism revealed an identical pattern for patient isolates that was different from the patterns of environmental isolates. Physicians should be aware of sporotrichosis in patients with ulcerative skin lesions who have a history of occupational or recreational exposure to sphagnum moss.

Lack of carcinogenesis by the baked mushroom Agaricus bisporus in mice: different feeding regimen [corrected]

Agaricus bisporus, the cultivated mushroom of the western hemisphere, was baked at 220-230 degrees C for 10 minutes and subsequently fed to mice for 12 hours each day, five days each week throughout their life. After each feeding cycle, the animals received a well-balanced semisynthetic diet for 12 hours each day for five days plus the remaining two full days each week. The estimated average daily mushroom consumption per animal was 4.8 g for a female and 4.2 g for a male. Randomly bred Swiss mice, six weeks old at the start of the experiment, were used. In the baked mushroom-fed group, the incidences of tumors in the lungs, blood vessels, cecum, and colon increased when compared to the untreated controls. These increases were not, however, statistically significant. In another previous experiment, both the raw and the baked mushrooms, when used in different feeding regimens, induced statistically significant incidences of cancers in several organs of the mice. It is possible that the negative finding in the current study was due to insufficient mushroom consumption.

Did the introduction of general practice fundholding change patterns of emergency admission to hospital?

OBJECTIVES

To test the hypothesis that the introduction of general practice fundholding was associated with a change in the proportion of emergency admissions to hospital.

METHODS

Before and after natural experiment with control group. The experimental group was first-wave fundholding general practices in the South Western Regional Health Authority, the control group was all practices that remained non-fundholding as of April 1993. Data were collected on episodes of care in hospitals in the South Western region involving cholecystectomy, hernia repair, intervertebral disc operation and prostatectomy. The additional impact of fundholding status on any underlying changes in proportions of emergency admissions was examined using multiple logistic regression.

RESULTS

There was no evidence of an interaction between fundholding status and before/after time period. Odds ratios and confidence intervals for the interaction of general practice fundholding status and time were: prostatectomy 1.02 (0.77 to 1.34); hernia repair 0.94 (0.7 to 1.24); intervertebral disk operations 1.67 (0.8 to 3.47); prostatectomy 0.94 (0.69 to 1.27).

CONCLUSIONS

The results provide no evidence that, in the first 2 years of the scheme, fundholding had an impact on the proportion of emergency admissions to hospital.

Subacute uremic and diabetic polyneuropathy

We present 4 patients who had a subacute, predominantly motor polyneuropathy associated with diabetes mellitus and end-stage renal disease. Electrophysiological studies and muscle biopsy indicated a primary axonal degeneration of nerve with secondary segmental demyelination, and mild to moderate, acute and chronic denervation of muscle. A relative absence of denervation potentials on needle electromyography was an unusual feature. Three of our patients improved with a switch from conventional to high-flux hemodialysis. We speculate on possible mechanisms.

Subacute uremic and diabetic polyneuropathy

We present 4 patients who had a subacute, predominantly motor polyneuropathy associated with diabetes mellitus and end-stage renal disease. Electrophysiological studies and muscle biopsy indicated a primary axonal degeneration of nerve with secondary segmental demyelination, and mild to moderate, acute and chronic denervation of muscle. A relative absence of denervation potentials on needle electromyography was an unusual feature. Three of our patients improved with a switch from conventional to high-flux hemodialysis. We speculate on possible mechanisms.

8-Arylguanine adducts from arenediazonium ions and DNA

Arenediazonium ions (ArN2+) are genotoxic though the source of their genotoxicity is unknown. The present studies were undertaken to determine if reductive decomposition of ArN2+ to aryl radicals (Ar) in the presence of calf thymus DNA (ctDNA) or in cells results in the formation of DNA adducts. We found that when arenediazonium ions of the general structure p-X-ArN2+ (X = CH3, CH2OCH3, CH2OH) are allowed to react with ctDNA or incubated with cells under conditions that produce p-X-Ar, DNA adducts are formed with guanine. The structure of the adduct is the C8-substitution product derived from guanine and p-X-Ar. Formation of p-X-Ar was determined by ESR spin-trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The extent of C8-arylguanine adduction was measured by high performance liquid chromatography (HPLC) analysis of the DNA hydrosylate and comparison with authentic synthetic standards. The C8-arylguanine adducts observed to form may be important in regard to the genotoxicity of ArN2+, though other DNA adducts such as the N6-triazene of adenine or C8-aryladenine adducts can form. Finally, though the formation of C8-arylguanine adducts from arenediazonium ions has been proposed, this is the first report demonstrating their formation in DNA.

A review of the antineoplastic action of certain hydrazines and hydrazine-containing natural products

The antineoplastic activities of hydrazines and hydrazine-containing natural products are summarized and reviewed. Many of these, including the base compound hydrazine, some of its 79 analogues and 2 hydrazine-containing cultivated mushrooms, exhibited antineoplastic actions in animals and some of them in humans. In addition, a substantial number of hydrazine analogues were further derivatized (altogether 331 derivatives were prepared) and studied to a limited extent for cancer chemotherapeutic activity in animals. Subsequently, only one hydrazine, N-isopropyl-alpha-(2-methylhydrazino)-p-toluamide HCl (procarbazine, natulan) was used extensively in human medicine. Because this drug is a highly carcinogenic substance in animals and since a substantial amount of evidence points to the possibility that it is co-carcinogenic or carcinogenic itself in humans, its use has largely been abandoned. Because well over 80% of the studied hydrazine class of compounds are carcinogenic, therefore, it may not be rewarding to search among them for cancer cure.

Mushroom toxins and cancer (review)

Significant advances have been made in recent years in cancer research concerning the chemistry and biological action of the various mushroom hydrazines and related chemicals as well as two mushrooms, Agaricus bisporus and Gyromitra esculenta. In addition, there is limited information involving the teratogenic effects of some of these mycotoxins. It is apparent that a series of these chemicals, as well as the feeding of two raw mushrooms, induce many cancers in experimental animals. Even though recent findings in the chemistry field indicate that the baked mushroom might act similarly to the raw mushroom with regard to cancer induction, no such studies to date have been undertaken. Thus far cancer epidemiologists have not initiated any research in revealing the effect of mushroom consumption in humans. The practical, frequent question as to whether to cease the consumption of some of the baked mushrooms cannot be answered until additional critical information becomes available. At present, there is no reason for the public to panic.

Gyromitra esculenta mushroom: a comparative assessment of its carcinogenic potency

A comparative assessment is performed on one of the false morel mushrooms, Gyromitra esculenta, including the amounts of some hydrazines present in this fungus, the cancer-inducing doses of these chemicals or the mushroom used in animal experiments, the total amounts of the hydrazines or mushroom needed to induce neoplasms in mice and the estimated total amounts of hydrazines or mushroom needed to induce cancer in humans. When one compares the estimated amounts of hydrazines required to induce cancer with the amount of raw Gyromitra esculenta needed to yield a similar effect, it becomes clear that to date 37 percent of the carcinogenic ingredients of this fungus have been identified.

Agaricus bisporus: an assessment of its carcinogenic potency

This assessment focuses on the concentrations of some chemicals present in the Agaricus bisporus mushroom, the cancer-inducing doses of these chemicals or mushroom used in the animal experiments, the total amounts of these chemicals or mushroom needed to induce cancer in these mice, and the estimated total amounts of these chemicals or mushroom needed to induce cancer in humans. By adding the estimated amounts of chemicals needed to induce cancer and by comparing it with the amount of raw mushroom needed to induce the same effect, it becomes obvious that we have accounted for less than 2% of the carcinogenic components of the Agaricus bisporus mushroom. Since some unavailable data handicapped this assessment, it should be regarded as tentative and subject to further adjustment.

A clinical evaluation of a blood conservation device in medical intensive care unit patients

OBJECTIVES

This study was designed to a) document the efficacy of a device intended to conserve blood in critically ill patients; b) determine the effect of this blood conservation on hemoglobin concentration and the need for blood transfusions; c) determine if the blood conservation device resulted in interference with arterial pressure waveforms; d) determine if use of the blood conservation device resulted in a difference in the number of accidental needle punctures suffered by healthcare workers.

DESIGN

Prospective, randomized, controlled trial. A clinical trial using prospective, random allocation of consecutive eligible patients.

SETTING

The medical intensive care unit (ICU) of a university hospital located in a large metropolitan area.

PATIENTS

A total of 100 patients who were admitted to the medical ICU, required arterial line monitoring for clinical purposes, and were managed by the ICU medical service. Exclusion criteria included active bleeding or chronic renal failure at the time of ICU admission.

INTERVENTIONS

Patients in the experimental group had a blood conservation device incorporated into the arterial pressure monitoring system, while patients in the control group received a conventional arterial pressure monitoring system.

MEASUREMENTS AND MAIN RESULTS

Data gathered included: age; gender; ICU discharge status; the duration of ICU stay; time in the study; volume of all blood drawn, discarded, or lost due to leakage; hemoglobin concentrations; blood transfusions; and accidental needle injuries. Arterial pressure waveforms were recorded and inspected for dampening or other deformation. Mean hemoglobin concentrations were compared on ICU admission and at 12-hr intervals. Demographic and clinical characteristics of the two groups were not significantly different. The volume of blood drawn and discarded from arterial catheters was significantly lower in the blood conservation group (blood conservation device: 5.7 +/- 7.5 mL; control: 96.4 +/- 88.5 mL; p < .0001), as was the total volume of blood discarded (blood conservation device: 19.4 +/- 47.4 mL; control: 103.5 +/- 99.9 mL; p < .0001). Mean hemoglobin concentration on admission was similar in the two groups (blood conservation device group: 11.8 +/- 2.5 g/dL; control group: 12.6 +/- 2.3 g/dL). In both groups, the mean hemoglobin concentration declined most rapidly in the first 24 hrs of ICU care and, thereafter, declined more slowly. Although the mean hemoglobin concentration was higher in the blood conservation group after 6 days, statistical significance was not reached until 9.5 days of ICU care. The mean change in hemoglobin concentration (overall: 1.2 +/- 2.2 g/dL) during the study represents a statistically significant (p < .0001) decrease of 9.7%. Hemoglobin concentration during the study decreased by 1.4 +/- 2.2 g/dL in the control group and 1.0 +/- 2.3 g/dL in the blood conservation group (p = nonsignificant). Univariate and multiple regression analysis demonstrated discarded blood volume to be a significant and independent predictor of the decline in hemoglobin concentration. Transfusion requirements were similar in both groups. The blood conservation system did not alter or interfere with pressure waveforms. There were no accidental needle injuries noted.

CONCLUSIONS

The conservation of blood in critically ill patients must be a high-priority concern of all healthcare workers. Our data indicate that the blood conservation system eliminates a significant factor in the decline in hemoglobin concentration. With devices as described here, there is no reason to continue the practice of wasting the blood of critically ill patients in order to prevent preanalytic error.

Teratogenic hydrazines: a review

The review summarizes the results of 30 hydrazines, which were studied in humans and in six animal species for teratogenic activities. Of these, 23 chemicals were found to induce physical defects in the developing embryos of animals. Six hydrazines failed to induce teratogenic abnormalities in animals under the experimental conditions. Three hydrazine analogues, some of which were given in combination with other drugs to pregnant women, gave ambiguous results concerning teratogenic effects. Some of these investigations were aimed at revealing the teratogenic mode of action of hydrazines. The mechanistic aspect focused on the dose requirements of chemicals and the time period in the development of the fetus susceptible to malformation and chemoprevention. Of interest is the base compound hydrazine, which was found to be teratogenic in five animal species. In general, the hydrazines were found to be powerful teratogens, which coincided in most cases with their known carcinogenic activities.

Bacterial mutagenicity of extracts of the baked and raw Agaricus bisporus mushroom

Aqueous extracts of baked and raw Agaricus bisporus (AB) mushroom were tested for mutagenic activity in Salmonella typhimurium strains TA1535 and TA1537. The extracts were studied with and without metabolic activation by Aroclor-induced rat liver S9 mix. The extracts of the baked and raw AB exhibited a dose related mutagenic activity with and without activation in strain TA1535. Similar findings were obtained in strain TA1537, although the net revertant values were of lower magnitude. Because humans mainly consume the cultivated mushroom AB in baked form, the implications of the findings are self-evident.

Cancer induction in mice by feeding the raw false morel mushroom Gyromitra esculenta

One of the false morel mushrooms, Gyromitra esculenta, was administered p.o. to Swiss mice that were 6 weeks old at the beginning of the experiment. The mushrooms were fed to the mice for 3 days and were followed by a semisynthetic diet for 4 days each week for life. The treatment induced tumors in the lungs, nasal cavity, blood vessels, forestomach, glandular stomach, cecum, and liver in the following incidences: 80, 10, 50, 16, 4, 28, and 6% in females, and 70, 12, 32, 18, 20, 22, and 12% in males. In the untreated controls, the corresponding tumor incidences were 28, 0, 14, 0, 0, 8, and 0% in females and 38, 0, 6, 0, 0, 8, and 2% in males. The light microscopic examination revealed the typical appearance of adenomas and adenocarcinomas of lungs, adenomas and adenocarcinomas of nasal cavities, hemangiomas and hemangiosarcomas of blood vessels, squamous cell papillomas and carcinomas of the forestomach, adenomas and adenocarcinomas of the glandular stomach, polypoid adenomas and adenocarcinomas of the cecum, and hepatomas. The work demonstrates the carcinogenic action of the raw G. esculenta mushroom.