Standard clinical computed tomography fails to precisely visualise presence, course and branching points of deep cerebral perforators.

BACKGROUND: Standard computed tomography (CT) images have earned a well-established position in neuroimaging. Despite that, CT is somehow limited by its resolution, which does not enable to distinctively visualise structures smaller than 300 µm in diameter. Perforating arteries, most of which measure 100-400 µm in diameter, supply important subcortical structures (thalamus, basal ganglia, internal capsule). Consequently, pathologies affecting these vessels (e.g. lacunar strokes) can have a devastating clinical outcome. The aim of our study was to assess standard CT's ability to visualise perforators and compare it with microscopic and micro-CT pictures. MATERIALS AND METHODS: We have obtained 6 brainstem and 17 basal ganglia specimens. We infused them with barium sulphate contrast medium administered into either vertebral or internal cerebral artery. After that, the specimens were fixed in formalin and subsequently a series of CT, micro-CT and microscopic examinations were performed. RESULTS: The median number of visualised perforators in brainstem and basal ganglia specimens was 8 and 3, respectively for CT and 18 and 7 for micro-CT (p < 0.05). Standard CT failed to clearly visualise branching points and vessels smaller than 0.25-0.5 mm (1-2 voxels) in diameter. Parallel vessels, like lenticulostriate arteries could not be differentiated in standard CT due to their proximity being smaller that the resolution. CONCLUSIONS: Basing on our results, we infer that CT is a poor modality for imaging of the perforators, presenting both quantitative and qualitative flaws in contrast with micro-CT.

Verification of the anatomy and newly discovered histology of the G-spot complex.

OBJECTIVES: To expand the anatomical investigations of the G-spot and to assess the G-spot's characteristic histological and immunohistochemical features. DESIGN: An observational study. SETTING: International multicentre. POPULATION: Eight consecutive fresh human female cadavers. METHODS: Anterior vaginal wall dissections were executed and G-spot microdissections were performed. All specimens were stained with haematoxylin and eosin (H&E). The tissues of two women were selected at random for immunohistochemical staining. MAIN OUTCOME MEASURES: The primary outcome measure was to document the anatomy of the G-spot. The secondary outcome measures were to identify the histology of the G-spot and to determine whether histological samples stained with H&E are sufficient to identify the G-spot. RESULTS: The anatomical existence of the G-spot was identified in all women and was in a diagonal plane. In seven (87.5%) and one (12.5%) of the women the G-spot complex was found on the left or right side, respectively. The G-spot was intimately fused with vessels, creating a complex. A large tangled vein-like vascular structure resembled an arteriovenous malformation and there were a few smaller feeding arteries. A band-like structure protruded from the tail of the G-spot. The size of the G-spot varied. Histologically, the G-spot was determined as a neurovascular complex structure. The neural component contained abundant peripheral nerve bundles and a nerve ganglion. The vascular component comprised large vein-like vessels and smaller feeding arteries. Circular and longitudinal muscles covered the G-complex. CONCLUSION: The anatomy of the G-spot complex was confirmed. The histology of the G-spot presents as neurovascular tissues with a nerve ganglion. H&E staining is sufficient for the identification of the G-spot complex.

Median aperture of the fourth ventricle revisited.

BACKGROUND: The median aperture of Magendie is the largest of three openings of the fourth ventricle and thus it forms the main path for the outflow of the cerebrospinal fluid from the ventricle. The Magendie aperture connects the fourth ventricle with the cisterna magna and makes a natural corridor for neurosurgical approach and inspection of the ventricle and its floor. The purpose of this study was to give a contemporary anatomical view of this structure in the context of historical data. MATERIAL AND METHODS: The Magendie foramen was studied in 30 fixed specimens of human brainstems with cerebella. The microdissection technique was used. Measurements were taken with a microscope ocular ruler. RESULTS: The aperture is limited by the following structures: obex and gracile tubercles inferiorly, and tela choroidea with choroid plexus superolaterally. Obex tubercles usually have the form of a piece of neural tissue bridging two halves of the brainstem above the entrance to the central canal. Gracile tubercles together are 8.15 mm wide and the maximal width of the foramen is 6.53 mm. Tela choroidea attaches laterally at both sides to the inferior medullary velum. In most cases the right and left choroid plexus are connected to each other with a triangular membrane of tela choroidea, which protrudes through the median foramen and attaches to the vermis at a highly variable level. CONCLUSIONS: We hope that the presented description of anatomical relations around the Magendie aperture, with its new measurements, will be helpful for those operating in the area and will explain some of the inaccuracies found in literature.

The anatomy of the fundic branches of the stomach: preliminary results.

The fundic branches of the stomach can be defined as a group of vessels that can arise either directly or indirectly from the following source arteries: the left inferior phrenic artery, the accessory left hepatic artery, the left gastric artery, the left middle suprarenal artery, the main trunk of the splenic artery, the posterior gastric artery, the superior polar artery, the gastrosplenic artery, the left gastroepiploic artery and the splenic artery with its inferior and superior terminal branches. It is worth mentioning that the fundic branches of the left gastroepiploic artery and the superior and inferior terminal branches of the splenic artery, like other vessels arising from these three source arteries and supplying the stomach, are defined as short gastric arteries. The anatomy of these fundic branches, particularly relevant to some surgical procedures, is not sufficiently described, and the current literature suffers from lack of publications on this particular topic. We therefore decided to explore in detail the arterial vascularisation of the gastric fundus. The research was carried out on material consisting of 15 human stomach specimens. The anatomical analysis comprised the following: the number of occurrences of fundic branches in each of the source arteries defined above, the distance between the origins of the source artery and its arising fundic branch, the way in which the fundic branches arose, the length, diameter at point of origin and morphology of the fundic branches, as well as the exact point of perforation of each fundic branch on the fundus. The highest incidence of the direct-branching pattern of fundic branches was in the left middle suprarenal artery, the gastrosplenic artery and the left gastrosplenic artery. The accessory left hepatic artery, the left gastric artery and the main trunk of the splenic artery were the most frequent site of the indirectly arising pattern of fundic branch. The highest median value of fundic branch length was 63.05 mm, found in the accessory left hepatic artery group. The largest median diameter value of the vessel was encountered among those originating in the left middle suprarenal artery and reached 2.17 mm. The posterolateral quadrant of the fundus received the largest number of fundic branches, amounting to 46.5% of all the fundic branches studied.

Chronic consumption of rebaudioside A, a steviol glycoside, in men and women with type 2 diabetes mellitus.

This trial evaluated the effects of 16 weeks of consumption of 1000mg rebaudioside A (n=60) a steviol glycoside with potential use as a sweetener, compared to placebo (n=62) in men and women (33-75 years of age) with type 2 diabetes mellitus. Mean+/-standard error changes in glycosylated hemoglobin levels did not differ significantly between the rebaudioside A (0.11+/-0.06%) and placebo (0.09+/-0.05%; p=0.355) groups. Changes from baseline for rebaudioside A and placebo, respectively, in fasting glucose (7.5+/-3.7mg/dL and 11.2+/-4.5mg/dL), insulin (1.0+/-0.64microU/mL and 3.3+/-1.5microU/mL), and C-peptide (0.13+/-0.09ng/mL and 0.42+/-0.14ng/mL) did not differ significantly (p>0.05 for all). Assessments of changes in blood pressure, body weight, and fasting lipids indicated no differences by treatment. Rebaudioside A was well-tolerated, and records of hypoglycemic episodes showed no excess vs. placebo. These results suggest that chronic use of 1000mg rebaudioside A does not alter glucose homeostasis or blood pressure in individuals with type 2 diabetes mellitus.

The hemodynamic effects of rebaudioside A in healthy adults with normal and low-normal blood pressure.

Rebaudioside A and stevioside are steviol glycosides extracted from the plant Stevia rebaudiana Bertoni and are used in several countries as food and beverage sweeteners. This randomized, double-blind trial evaluated the hemodynamic effects of 4weeks consumption of 1000mg/day rebaudioside A vs. placebo in 100 individuals with normal and low-normal systolic blood pressure (SBP) and diastolic blood pressure (DBP). Subjects were predominantly female (76%, rebaudioside A and 82%, placebo) with a mean age of approximately 41 (range 18-73) years. At baseline, mean resting, seated SBP/DBP was 110.0/70.3mmHg and 110.7/71.2mmHg for the rebaudioside A and placebo groups, respectively. Compared with placebo, rebaudioside A did not significantly alter resting, seated SBP, DBP, mean arterial pressure (MAP), heart rate (HR) or 24-h ambulatory blood pressures responses. These results indicate that consumption of as much as 1000mg/day of rebaudioside A produced no clinically important changes in blood pressure in healthy adults with normal and low-normal blood pressure.

Microbial hydrolysis of steviol glycosides.

A review of the role of gut microbiota in the metabolism of the steviol glycosides, stevioside and rebaudioside A, indicates that they are not absorbed intact but undergo hydrolysis by the intestinal microflora to steviol. Steviol is not metabolized by the intestinal flora and is absorbed from the intestine. The rate of hydrolysis for stevioside is greater than for rebaudioside A. Recent studies using mass spectrometry have shown that steviol-16,17-epoxide is not a microbial metabolite of steviol glycosides. Bacteroides species are primarily responsible for hydrolysis via their beta-glucosidase activity. Fecal incubation studies with both human and animal mixed flora provide similar results, and this indicates that the rat is an appropriate model for studies on steviol glycosides. Given the similarity in the microbial metabolism of stevioside and rebaudioside A with the formation of steviol as the single hydrolysis product that is absorbed from the intestinal tract, the toxicological data on stevioside are relevant to the risk assessment of rebaudioside A.

Determination of conjugated linoleic acid (CLA) concentrations in milk chocolate.

The fatty acids from a series of milk-chocolate-based confectionery samples were analyzed as methyl esters by GC to determine the presence and amount of conjugated linoleic acid (CLA). A single peak corresponding to the 9-cis,11-trans isomer and ranging from less than 0.1% to nearly 0.2% of the total fatty acids, corresponding to up to 0.3 mg per g of chocolate, was observed. One of the chocolate extracts and a milk extract were subjected to silver ion HPLC and GC-MS in order to confirm the identity of the major isomer and tentatively identity minor isomers.

Chronic toxicity/carcinogenicity studies of cocoa powder in rats.

Cocoa powder (CP) was fed at levels of 0.0 (control), 1.5, 3.5 and 5.0% for 104 wk to male and female Sprague-Dawley rats derived from the F3b generation of a multigeneration study using the same CP diets. Initial methylxanthine intake was high in all treatment groups, but steadily declined until wk 26. The high dose level provided a mean methylxanthine intake of approximately 57 mg/kg body weight/day for males and 74 mg/kg body weight/day for females from wk 26 to wk 104 of the study. Compared with controls, the historical trend of methylxanthine-associated growth stimulation was evident in rats consuming diets containing 1.5% CP, while body weight was reduced in rats consuming diets containing 3.5 and 5.0% CP. Survival rates were similar in control and CP-fed rats. No evidence of treatment-related clinical disease or ocular effects was noted. An increased incidence of bilateral testicular atrophy and aspermatogenesis was present in males consuming diets containing 5.0% CP. Non-suppurative myocarditis and interstitial fibrosis of the heart were also increased in incidence in both sexes receiving diets containing 5.0% CP. The overall incidences of both pelvic dilatation and renal pelvic microcalculi were increased in most treatment groups. Although there was no difference in the incidence of benign mammary gland fibroadenomas in female rats between the control group and any CP-fed group, a marginally significant (P = 0.04) trend test was apparent. The significance of this finding is doubtful, since the incidence of this lesion in the highest dose group was well within the historical control range for this strain of rats. No evidence of carcinogenicity from dietary CP was found in either sex.

Three-generation reproductive study of cocoa powder in rats.

Male and female Sprague-Dawley rats were continuously exposed to dietary cocoa powder at levels of 0.0, 1.5, 3.5 or 5.0% for three generations. During the initial 12-wk growth periods for the F0-, F1b- and F2b-generation rats, mean methylxanthine exposures (mg/kg/day) for males/females were 30/36, 72/86 and 104/126 for the 1.5, 3.5 and 5.0% cocoa powder groups, respectively. No consistent dose-related effects on any of the monitored reproductive indices (mating, fertility, conception, gestation, viability or lactation) were noted over three generations. Minor reductions in mean body weight relative to controls at wk 12 were observed in male rats exposed to 3.5 or 5.0% cocoa powder and female rats exposed to 5.0% cocoa powder in the F1b and F2b generations. Renal tubular mineralization in the F0-generation male rats in the 5.0% cocoa powder group was the only statistically elevated histomorphological lesion observed. Plasma cholesterol concentrations in F1b-generation rats were elevated, but cocoa powder did not affect this parameter consistently across multiple generations. Thus, continuous cocoa powder consumption by rats at levels as high as 5.0% of the diet was without effect on reproductive capacity under the conditions of a standard three-generation evaluation.

[A case of diphtheria in a young man]. / Przypadek blonicy gardla u mlodego mezczyzny.

A case of pharyngeal diphtheria with mild course was observed in a man aged 21 years who had had received four vaccinations. This was the first case of this disease in Poland since 1983, and the possibility is discussed of diphtheria spread in a country with widespread Di-Per-Te vaccinations, as pointed out in the present literature.

Digestibility of cocoa butter and corn oil and their influence on fatty acid distribution in rats.

The comparative bioavailability of cocoa butter (a predominantly saturated fat) and corn oil (a predominantly unsaturated fat) was determined in male Sprague-Dawley rats by analysis of total fecal lipids following ad libitum feeding of purified diets containing 5, 10 and 20% cocoa butter or corn oil for 2 wk. Fecal lipid elimination was significantly increased (P less than 0.05) in each cocoa butter group when compared with the corresponding corn oil group, resulting in lower digestibility coefficients for cocoa butter (59-72%) than for corn oil (93-97%). Body weight gain and food intake data were similar among all treatment groups. Fecal fatty acid profiles in rats fed corn oil diets consisted primarily of 27-34% palmitic acid (16:0), 22-32% stearic acid (18:0) and 25-37% oleic acid (18:1). Palmitic, oleic and linoleic acids were also the primary fatty acids stored in epididymal fat tissue from corn oil-fed rats. In contrast, fecal fatty acids in animals fed cocoa butter diets consisted of 31-37% palmitic acid and 58-64% stearic acid; oleic acid was the major fatty acid stored in epididymal fat tissue. These results indicate that the decreased digestibility of cocoa butter is largely a result of its fatty acid composition. This reduced bioavailability of cocoa butter may be at least partially responsible for its previously described neutral effect on serum cholesterol.

Diet-induced alterations in theobromine disposition and toxicity in the rat.

To assess the potential influence of diet on theobromine (TBR) disposition and the development of TBR-induced thymic and testicular toxicity, male Sprague-Dawley rats were given the following diets ad libitum for 28 days: (1) semipurified (S); (2) commercial chow (Ch); (3) semipurified + 0.6% TBR (S + TBR); or (4) commercial chow + 0.6% TBR (Ch + TBR). Toxicity endpoints determined in each TBR group indicated that Ch + TBR-treated animals did not exhibit the marked reduction in body weight or testicular atrophy induced by the S + TBR diet, although thymic weight was lower regardless of diet. Metabolic studies performed after the 28-day feeding period using 5 mg/kg TBR + 10 microCi [8-14C]TBR revealed an overall inductive effect of Ch on TBR metabolism as shown by increased urinary excretion (0-24 hr) of the major TBR metabolite, 6-amino-5[N-methylformylamino]-1-methyluracil (6-AMMU), as well as 7-methylxanthine + 3-methylxanthine (7-MX + 3-MX) and 3,7-dimethyluric acid (3,7-DMU). Consumption of 0.6% TBR for 28 days in either S or Ch diets also induced its own metabolism, as shown by decreased urinary excretion of unchanged TBR and increased conversion primarily to 3,7-DMU. Fecal 14C elimination (0-24 hr) was similar between animals fed S and Ch diets, indicating no effect of control diet on TBR bioavailability. Since serum TBR concentrations and overall toxicity were lower in Ch + TBR-treated animals than in S + TBR treated animals, yet TBR bioavailability was similar, this effect was attributed to the inducing potential of the Ch diet on TBR metabolism and clearance. Investigators are cautioned to consider the potential effect of diet on metabolism when performing and evaluating toxicological studies.

Evaluation of the teratogenic potential of cocoa powder and theobromine in New Zealand White rabbits.

Studies were conducted to determine the teratogenic potential of theobromine (TBR) and cocoa powder (CP) in rabbits. TBR was given either by gavage at dose levels of 0, 25, 75, 125 or 200 mg/kg body weight/day or administered in the diet at 0, 0.0625, 0.125 or 0.1875% (approximately 0, 21, 41 or 63 mg/kg/day, respectively). CP was given at 2.5, 5.0 or 7.5% of the diet (approximately 25, 50 or 75 mg methylxanthines/kg body weight/day). The duration of exposure was from days 6 to 29 of gestation. Significant maternal mortality (40%) and reduced food consumption were observed at 200 mg TBR/kg/day. Mean foetal weights were similar to those of the control group at 25 or 75 mg TBR/kg/day, but decreases in foetal body weight and increases in various malformations and developmental variations were observed in groups given 125 or 200 mg/kg/day. Insufficient litters were available for examination in the 200-mg/kg/day dose group because of maternal toxicity/lethality (repetitive exposure by gavage to 200 mg TBR/kg approached the maternal LD50). In the dietary CP studies, three does died and three aborted, but these deaths and abortions were not treatment related. No maternal deaths occurred during dietary TBR exposure. Maternal weight gain and food consumption, and the mean number of corpora lutea were unaffected by either dietary CP or TBR. Neither foetotoxicity nor teratogenicity was associated with dietary ingestion of CP or TBR. The foetuses exposed to 0.125% or 0.1875% TBR had a significantly higher incidence of incompletely ossified or absent sternebrae, whereas exposure to 0.1875% or 7.5% CP resulted in corresponding effects on metacarpal bones, indicating a delay in osteogenesis. The predominant compound found in serum after TBR ingestion was unchanged TBR, and there was no evidence of bioaccumulation of TBR in serum during gestation. The highest levels of CP or TBR used in these studies was 38 times greater than the maximum consumption level reported for humans in marketing surveys, and corresponds to a consumption of greater than 7.5 lb milk chocolate/day.

Evaluation of the perinatal, postnatal and teratogenic effects of cocoa powder and theobromine in Sprague-Dawley/CD rats.

Studies were conducted to evaluate the effects of cocoa powder (CP) and theobromine (TBR) on perinatal and postnatal parameters and to assess their potential teratogenicity in the rat. In the peri/postnatal study, CP was given at 0, 2.5, 5.0 or 7.5% in the diet throughout gestation and lactation (postnatal day 21). In the teratology study, rats were given diets containing 0, 2.5 or 5.0% CP or 0.0675 or 0.135% TBR on days 6-19 of gestation. The CP-treated dams in the peri/postnatal study consumed significantly more food than did the controls during gestation. Weight gain was increased only in the 5.0 and 7.5% CP groups during lactation. Litter size was reduced slightly at 7.5% CP and pup survival was slightly decreased at 5.0 and 7.5% CP but none of these reductions was statistically significant. However, small but statistically significant decreases in pup body weights were noted in all treatment groups throughout lactation. In the teratology studies, rats given 2.5 or 5.0% CP or 0.0675 or 0.135% TBR consumed significantly more food than did the controls and the CP-treated dams gained significantly more weight. The percentage of pregnant dams and the mean number of corpora lutea were not affected by either CP or TBR. Foetuses exposed to 0.135 TBR had a significantly higher incidence of incompletely ossified or absent sternebrae and pubic bones, indicating a delay in osteogenesis. On the basis of the survival of treated offspring in the peri/postnatal study, these effects were not considered to be deleterious to either growth or survival. The effects are similar to those that have been reported elsewhere and been considered to indicate potential maternal or foetal toxicity that is unrelated to a specific compound/treatment. We conclude that any variations observed in these studies may be attributed to this non-specific maternal toxicity and are not related to the ingestion of either CP or TBR. The major methylxanthine found in the serum after CP or TBR ingestion was unchanged TBR and it did not bioaccumulate during gestation. The levels of CP and TBR used in these studies were more than 50 times greater than the maximum level of consumption by humans as reported in marketing surveys and were equivalent to a consumption of 10 lb of milk chocolate per day. The results indicate that neither CP nor TBR pose any health hazard to the developing foetus.

Genotoxicity of theobromine in a series of short-term assays.

Theobromine (3,7-dimethylxanthine) was evaluated for genotoxic activity in a series of in vitro assays. Theobromine was not mutagenic in the Ames assay up to a maximum concentration of 5000 micrograms/plate either with or without S9 activation. The compound also failed to induce significant levels of chromosome aberrations in CHO cells (with and without S9 activation) or transformation in Balb/c-3T3 cells. At the maximum tolerated concentration theobromine increased the frequency of TK-/- mutants in mouse lymphoma L5178Y cells. Increased frequencies were observed both with and without S9 activation and they were reproducible in 2 independent experiments. Statistically significant increases in SCEs were obtained in human lymphocytes and in CHO cells under nonactivation test conditions. The spectrum of results in this battery of tests indicate that theobromine treatment results in the expression of genotoxic potential in some assays and the observed activity appears qualitatively and quantitatively similar to that of caffeine, a closely related methylxanthine.

Genotoxicity of cocoa in a series of short-term assays.

Cocoa powder was evaluated for genotoxic activity and found to be inactive in the Ames assay, the mouse lymphoma assay, cytogenetic assays measuring chromosome breakage and SCE, and a cell transformation assay using Balb/c-3T3 cells. Although pure theobromine has been shown to be active in some of these test procedures, the levels of this methylxanthine present in cocoa powder were insufficient to elicit responses in this battery of tests.

Postprandial glucose and insulin responses to various snacks of equivalent carbohydrate content in normal subjects.

To evaluate glucose and insulin responses after ingestion of snacks, we gave healthy, nondiabetic male subjects carbohydrate equivalent (25 g) snacks or isocaloric (265 kcal) snack meals in a random crossover design. Individual snacks composed of either a milk chocolate bar, granola bar, chocolate milk, peanut butter cups, yogurt, or potato chips produced similar glucose response curves. Plasma glucose concentrations were lower (p less than or equal to 0.05) at 30 and 60 min postprandially than after a corresponding oral glucose challenge. In contrast, insulin responses to the snacks exhibited a two-fold variation in peak values. Isocaloric snack meals of cereal-milk, cheese sandwich-milk, and peanut butter sandwich-chocolate milk produced glucose and insulin responses similar to individual snacks. Although glucose concentrations at 60 min fell somewhat below baseline values after each snack, clinical hypoglycemia was not evident. These data clearly indicate a similarity in glycemic response among normal individuals consuming a variety of common snacks.

High levels of methylxanthines in chocolate do not alter theobromine disposition.

Theobromine disposition was measured twice in 12 normal men, once after 14 days of abstention from all methylxanthines and once after 1 week of theobromine (6 mg/kg/day) in the form of dark chocolate. Mean theobromine t 1/2, apparent volume of distribution, and clearance after abstinence from all methylxanthines were 10.0 hours, 0.76 L/kg, and 0.88 ml/min/kg. High daily doses of chocolate for 1 week did not change these values. After subjects abstained from methylxanthines, urinary radioactivity over 72 hours after a single, oral dose of [8-14C]theobromine consisted of 42% 7-methylxanthine, 20% 3-methylxanthine, 18% theobromine, 10% 7-methyluric acid, and 10% 6-amino-5[N-methylformylamino]-1-methyluracil. A week of daily theobromine consumption in the form of dark chocolate also did not alter this urinary profile of theobromine and its metabolites. Although these results might appear to differ from other reports of inhibition of theobromine elimination after five consecutive daily doses of theobromine in aqueous suspensions, both the rate and extent of absorption of theobromine in chocolate were less than that of theobromine in solution. Relative bioavailability of theobromine in chocolate was 80% that of theobromine in solution. This reinforces the fundamental principle that both the metabolic and the therapeutic consequences of a particular chemical can differ when that chemical is given in the pure compared with the dietary form.