Pharmacognostical and phytochemical studies of Atibala (Abutilon indicum [Linn.] sweet) fruit

Background

Abutilon indicum (Linn.) Sweet (Malvaceae), generally called as "Atibala" is a plant of high medicinal importance. The plant possesses several beneficial effects such as cooling, laxative, digestive, analgesic, anti-inflammatory, astringent, diuretic, expectorant, antihelmintic, aphrodisiac, and demulcent which is widely used in the Ayurveda system of medicine.

Aim

The current study is aimed to establish the macroscopy, powder microscopy and physicochemical analysis of A. indicum fruits.

Materials and methods

The Pharmacognostical studies on A. indicum fruits, including parameters such as morphological evaluation, powder microscopy, ash values, foreign organic matter, extractive value, phytochemical, fluorescence studies, and high-performance thin-layer chromatography fingerprint profile, are established in the current study.

Results

Fruit powder microscopy has shown diagnostic characteristics such as stellate hairs of different sizes, testa, lignified endocarp, and palisade cells. The loss on drying value of fruit powder was 7.7% w/w. The total ash values of the drug were found to be 10.5% and acid insoluble ash 2.4% w/w with respect to the air-dried crude drug. Water-soluble and alcohol-soluble extractives were found to be 9.64% w/w and 9.04% w/w, respectively.

Conclusion

Phytochemical characterization of aqueous, alcoholic extracts of A. indicum fruit revealed the presence of proteins, carbohydrates, phenols, flavonoids, saponins, and steroids. The powder microscopical and phytochemical studies observed in this study can serve as a valuable resource for the authentication of A. indicum fruits.

Tissue distribution of mercury and copper after Aarogyavardhini Vati treatment in rat model of CCl4 induced chronic hepatotoxicity

Background

Aarogyavardhini Vati is a classical Ayurvedic herbomineral formulation. It contains mercury and copper compounds as principal minerals along with other minerals and herbal ingredients. Aarogyavardhini Vati is indicated in chronic liver ailments. However, safety concerns are often raised regarding the use of mercury containing ayurvedic drugs in disease conditions due to the risk of mercury and copper toxicity.

Objective

This study was performed to address the safety concerns regarding mercury and copper toxicity from Ayurvedic herbomineral formulations by investigating accumulation of these minerals in tissues and subsequent toxicity in chronic hepatotoxicity rat model.

Materials and methods

Quantification of mercury and copper in Aarogyavardhini Vati was done. Chronic hepatotoxicity was induced in the Wistar rats by repeated administration of CCl₄ for 8 weeks. Animals were treated with Aarogyavardhini Vati for various durations. Post treatment of 8 weeks, serum biochemical marker estimations was done. Estimation of mercury and copper from the liver, kidney and brain tissues was done after animal sacrifice. Histopathology evaluation of visceral organs was also performed.

Results

Treatment with Aarogyavardhini Vati exhibited significant accumulation of mercury in the kidney but not in the brain and liver. Similarly, no significant accumulation of copper was observed in liver, kidney, and brain due to the treatment of Aarogyavardhini Vati. Serum biochemical and histopathological changes were not affected by the treatment with Aarogyavardhini Vati.

Conclusion

Aarogyavardhini Vati did not show any biologically significant potential to cause toxicity due to its mercury and copper content when administered for prolonged duration to rats with chronic hepatotoxicity.

Effect of Coelogyne cristata Lindley in alleviation of chronic fatigue syndrome in aged Wistar rats

BACKGROUND

Swarna Jibanti scientifically known as Coelogyne cristata Lindley (Orchidaceae), an orchid mentioned in Ayurvedic medicine is used to promote healthy life span.

OBJECTIVE(S)

The present work was planned to study the efficacy of hydro-alcoholic extract of pseudobulbs of C. cristata (CCE) to assess its role on chronic fatigue syndrome (CFS) induced behavioural and biochemical changes in aged Wistar rats compared to Panax ginseng (PG), a prototype anti-stress agent.

MATERIALS AND METHODS

CFS was induced by forced swimming for consecutive 21 days for fixed duration (15 min sessions). The criteria of CFS due to fatigue were counted using locomotor activity, depression and anxiety through automated photactometer, immobility time and plus maze activity respectively. Acute toxicity study of CCE (upto 2 g/kg, Limit test) was also performed. For CFS, animals were divided into five groups, naive control, control, CCE treated (25 mg/kg b.w., 250 mg/kg b.w.) and standard PG treated (100 mg/kg b.w.) groups. All drugs were given orally for consecutive 21 days along with CFS. After assessing behavioural parameters, all animals were sacrificed at day 21 and in vivo antioxidant potential of CCE was determined by lipid peroxides, nitrite, catalase (CAT) and superoxide dismutase (SOD) in brain tissue.

RESULTS

CCE was found to be non-toxic. CCE treated aged rats significantly improved (p < 0.001) the spontaneous locomotor movement with respect to control rats, while, decreased the mobility period or depression score. In CFS, CCE also enhanced the time spent (p < 0.001) in open arms while reducing the time spent in closed arm as compared to CFS control, indicating lowering anxiety score. Moreover, marked diminution in lipid peroxidation, nitrite and SOD level was exhibited after CCE treatment and significantly enhanced catalase level significantly (p < 0.01) with respect to CFS control. PG also showed similar actions.

CONCLUSION

The results confirmed the potential therapeutic actions of CCE against experimentally induced CFS in aged rats that might be due to its CNS mediatory antioxidant properties.

Symmetry and the geometric phase in ultracold hydrogen-exchange reactions

Quantum reactive scattering calculations are reported for the ultracold hydrogen-exchange reaction and its non-reactive atom-exchange isotopic counterparts, proceeding from excited rotational states. It is shown that while the geometric phase (GP) does not necessarily control the reaction to all final states, one can always find final states where it does. For the isotopic counterpart reactions, these states can be used to make a measurement of the GP effect by separately measuring the even and odd symmetry contributions, which experimentally requires nuclear-spin final-state resolution. This follows from symmetry considerations that make the even and odd identical-particle exchange symmetry wavefunctions which include the GP locally equivalent to the opposite symmetry wavefunctions which do not. It is shown how this equivalence can be used to define a constant which quantifies the GP effect and can be obtained solely from experimentally observable rates. This equivalence reflects the important role that discrete symmetries play in ultracold chemistry and highlights the key role that ultracold reactions can play in understanding fundamental aspects of chemical reactivity more generally.

Ninety days repeated dose oral toxicity study of Makaradhwaja in Wistar rats

Context:

Makaradhwaja is a KupipakwaRasayana. Since it contains two heavy metals, namely mercury and gold, it is essential to evaluate its safety. Hence, the present study was undertaken with an objective to evaluate toxicity and target organ of toxicity of Makaradhwaja if so.

Aims:

The objective was to evaluate toxicological profile, the target organ of toxicity and to find no observed effect level (NOEL) or no observed adverse effect level (NOAEL) in rats after oral administration for ninety consecutive days.

Materials and Methods:

Makaradhawaja preparation was administered to male and female Wistar rats for ninety consecutive days at 2.7, 13.5, and 27 mg/kg body weight. All relevant biochemical and hematological changes were observed. At termination, all the rats were sacrificed and necropsy was performed. Histopathological evaluation was also performed.

Statistical Analysis Used:

Dunnett's test followed by analysis of variance.

Results:

There was a significant increase in high-dose group kidney weight of both sexes which could not be correlated with histopathology findings and serum biochemistry. Therefore, the change was not considered as an adverse effect.

Conclusions:

The dose level 27 mg/kg of Makaradhwaja was found as NOAEL and dose level 13.5 mg/kg of Makaradhwaja was found as NOEL.

A single case study of treating hypertrophic lichen planus with Ayurvedic medicine

Ayurvedic medicines are often considered effective for chronic and lifestyle disorders. Hypertrophic lichen planus (HLP) is a rare inflammatory skin condition and develops into squamous cell carcinoma in few cases. It has resemblance with Charma Kushtha mentioned in Ayurvedic classics. Conventional therapy used in this condition is unsatisfactory and is not free from side effects. A case of long-standing systemic steroid-dependent HLP is presented here which was intervened successfully with Ayurvedic modalities.

Experimental and histopathological observation scoring methods for evaluation of wound healing properties of Jatyadi Ghrita

Introduction:

Jatyadi ghrita is a classical Ayurvedic formulation indicated in the treatment of various types of ulcers.

Aim:

The study was designed to explore the wound healing properties of Jatyadi Ghrita in diabetes - induced rats.

Materials and Methods:

In the present study, diabetes mellitus was induced to 6 to 8-week-old male Wistar rats by injecting streptozotocin cut 65 mg/kg body weight intravenously by 15 min prior to the administration of Nicotinamide at 230 mg/kg body weight intraperitoneally. Animals having diabetes were used for grouping namely, diabetic control (DC), Ghrita control (GC), positive control (PC), i.e., mupirocin HCl, Jatyadi Ghrita treatment and one group of non-DC. Full-thickness excision wound was created and diameter was recorded. Daily clinical observations were recorded. A wound scoring method was developed. Wound diameter and score were recorded on days 1, 2, 3, 5, 7, 9, 12, 14 and 15. Photographs were taken at the same time interval points. Body weight and feed consumption were recorded weekly. Animals were sacrificed at regular intervals to collect the wound area tissue for histopathology analysis. Obtained data was analyzed statistically.

Results and Observation:

It was observed that there was no significant difference in diameter and percent change in wound healing as compared to any control. However, clinical score and histopathological changes in Jatyadi Ghrita group were improved from the second day of the study as compared to control.

Conclusion:

This indicates that the drug has similar wound healing activity as compared to the modern drug mupirocin HCl.

The prevalence of dyslipidemia in patients with diabetes mellitus of ayurveda Hospital

Background

Dyslipidemia is one of the major risk factors for cardiovascular disease in diabetes mellitus. Early detection and treatment of dyslipidemia in type-2 diabetes mellitus can prevent risk for atherogenic cardiovascular disorder. The rationale of this study was to detect the lipid abnormality in diabetic patients.

Methods

Necessary data was collected from the medical archives of 150 patients (73 female and 77 male) with diabetes mellitus registered in Department of pathology and biochemistry of a Ayurveda hospital established at Kolkata, India.

Results

The mean ages of female and male subjects were 51.8 ± 10.8 and 53.2 ± 11.3 years respectively. The range and mean value of FBS in females were 113–342 mg/dl and 157.7 ± 6.3 mg/dl, while the range and mean value of PPBS in females were 135–560 mg/dl and 275.5 ± 12.3 mg/dl respectively. Results showed that range and mean value of FBS in males were 111–462 mg/dl and 160.8 ± 7.4 mg/dl, while the range and mean value of PPBS in males were 136–598 mg/dl and 302.1 ± 12.6 mg/dl respectively. Results of serum lipids showed that the mean values for total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) in female patients were 202.2 ± 5.9 mg/dl, 168.3 ± 8.2 mg/dl, 44.9 ± 1.3 mg/dl, 123.6 ± 5.2 mg/dl and 33.7 ± 1.7 mg/dl respectively. The mean values for TC, TG, HDL-C, LDL-C and VLDL-C in male patients were 182.5 ± 4.8 mg/dl, 128.1 ± 10.8 mg/dl, 40.8 ± 1.2 mg/dl, 105.4 ± 4.8 mg/dl and 36.2 ± 2.2 respectively. FBS showed significant positive correlation with PPBS, cholesterol, TG, and VLDL-C. PPBS also demonstrated direct and significant correlations with TG and VLDL-C.

Conclusions

The study showed common lipid abnormalities during diabetes induced dyslipidemia i.e., hypercholesterolemia, hypertriglyceridemia and elevated LDL-C. This study suggests the dominance of hyperlipidemia over increased prevalence of dyslipidemia.

Repeated dose oral toxicity of Trivanga Bhasma in Swiss albino mice

Trivanga Bhasma, a metallic preparation containing Bhasmas of Naga (lead), Vanga (tin) and Yashada (zinc), was studied for repeated dose toxicity in Swiss albino mice to estimate No Observed Effect Level (NOEL) or No Observed Adverse Effect Level (NOAEL). A total of 80 Swiss albino mice of either sex with an average body weight of 28-30 g were equally divided into four groups (Group I, II, III, and IV). Group I served as control and was given vehicle (honey: water in 2:3 ratio) Group II, III, and IV received Trivanga Bhasma @ 7.8, 39.5,and 78 mg/kg body weight for 90 consecutive days. The effect of drug was assessed on body weight, feed and water consumption changes, hematological, and histopathological parameters. At the end of the study, all animals were sacrificed and examined for gross pathological changes. Histopathological evaluation was performed for control and high dose group. Trivanga Bhasma was found to be safe. No significant clinical signs were noted in all groups studied. No major alterations were observed during histopathological evaluation. Hence, dose rate of 78 mg/kg body weight was established as NOAEL. It is suggested to carry out a toxicity study at possible higher doses and in a different species so as to establish target organ of toxicity.

Toxicological evaluation of Panchakola Avaleha, an Ayurvedic classical formulation, in albino rats

The present study was carried out to assess the safety of standardized Panchakola Avaleha on albino rats (Wistar strain). Animals were administered three doses of Panchakola Avaleha by oral routes, viz. higher (500 mg/kg/day), middle (250 mg/kg/day), and therapeutic dose (50 mg/ kg/ day) for 28 consecutive days. Effects of the test drug on hematological, biochemical, and histopathologic parameters were evaluated. This study revealed normal behavior, no mortality, and no significant changes in hematological, biochemical, and histopathological examinations.

Spontaneous Nonmetastatic Choriocarcinoma, Yolk Sac Carcinoma, Embryonal Carcinoma, and Teratoma in the Testes of a Swiss Albino Mouse

A 12-week-old Swiss Albino mouse was presented with unilateral (left) testicular enlargement of approximately 1.5 cm in diameter and the right testicle mildly reduced in size and weight. Histopathology evaluation revealed three distinct neoplasms in the left testicle: choriocarcinoma, yolk sac carcinoma, and embryonal carcinoma. Teratoma was diagnosed in the right testicle. The histomorphological and immunohistochemical characteristics of the tumor are presented here. To the best of the authors’ knowledge, this is the first report of spontaneous nonmetastasizing choriocarcinoma, yolk sac carcinoma, embryonal carcinoma, and teratoma in testes of a Swiss albino mouse.

Adjunct therapy of Ayurvedic medicine with anti tubercular drugs on the therapeutic management of pulmonary tuberculosis

BACKGROUND

Pulmonary tuberculosis (PTB) is an age old disease described in Vedic Medicine as 'Yakshma'. Later on, in Ayurveda it earned a prefix and found way into mythology as 'Rajayakshma'. After the discovery of streptomycin, the therapeutic management of PTB received a major breakthrough. The treatment module changed remarkably with the formulation of newer anti-tubercular drugs (ATD) with appreciable success. Recent resurgence of PTB in developed countries like United States posed a threat to the medical community due to resistant strains. Consequently, WHO looked toward traditional medicine. Literature reveals that Ayurvedic treatment of PTB was in vogue in India before the introduction of ATD with limited success. Records show that 2766 patients of PTB were treated with Ayurvedic drugs in a tertiary care hospital in Kolkata in the year 1933-1947.

OBJECTIVES

To evaluate the toxicity reduction and early restoration by adjunct therapy of Ayurvedic drugs by increasing the bio-availability of ATDs.

MATERIALS AND METHODS

In the present study, treatment response of 99 patients treated with ATD as an adjunct with Aswagandha (Withania somnifera) and a multi-herbal formulation described in Chikitsa-sthana of Charaka samhita i.e. Chyawanprash were investigated. Hematological profile, sputum bacterial load count, immunoglobulin IgA and IgM, blood sugar, liver function test, serum creatinine were the assessed parameters besides blood isoniazid and pyrazinamide, repeated after 28 days of treatment.

RESULTS

The symptoms abated, body weight showed improvement, ESR values were normal, there was appreciable change in IgA and IgM patterns and significantly increased bioavailability of isoniazid and pyrazinamide were recorded.

CONCLUSION

This innovative clinical study coupled with empowered research may turn out to be promising in finding a solution for the treatment of PTB.

Effect of α-tocopherol on salivary reactive oxygen species and trace elements in oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSMF) is a chronic debilitating disease and a well-recognized, potentially malignant condition of the oral cavity associated with betel quid chewing. Betel quid chewing is a popular oral habit in India and shows strong association in the incidence of OSMF. The objective of the study was to determine the levels of trace elements, pro-oxidants and reactive oxygen species (ROS) in saliva of betel quid chewers and OSMF patients, which may help in the diagnosis of cancer progression in the oral cavity.

METHODS

A total of 35 cases of OSMF and 35 cases of healthy individuals were included in the present study. The salivary status of ROS, pro-oxidants and some trace elements was studied in OSMF patients and normal healthy individuals.

RESULTS

The levels of lipid peroxides (P < 0.001), conjugated dienes (P < 0.01), hydroxyl radicals (P < 0.01), superoxide dismutase (P < 0.05), copper (P < 0.05), calcium (P < 0.01), magnesium (NS), potassium (P < 0.05) and iron (P < 0.05) in OSMF patients were elevated when compared with normal healthy individuals. The levels of hydrogen peroxide (P < 0.05) and sodium (P < 0.01) in OSMF patients were found to be decreased when compared with control subjects. A significant alteration was noticed after supplementing with α-tocopherol in oral precancerous patients.

CONCLUSION

These parameters may help in the detection of the severity of oral diseases.

A Spontaneous Teratocarcinoma in the Testis of a Swiss Albino Mouse

A unilateral non-metastatic embryonal carcinoma and teratoma of the testis was observed in a 12-week-old Swiss Albino mouse at the end of a 28-day repeated dose toxicity study. The teratocarcinoma almost completely replaced the parenchyma of the left testis. The tumor was composed of sheets and rosettes of primitive embryonal cells, anaplastic cells, skeletal muscle tissue, sebaceous gland tissue, keratinized stratified squamous epithelium, and ciliated cuboidal epithelium. The histomorphological characteristics of the tumor were reviewed and presented in this report. To the best of the authors' knowledge, this is the first report of spontaneous teratocarcinoma of testis in the Swiss Albino strain of mice.

Manipulating higher partial-wave atom-atom interactions by strong photoassociative coupling

We show that it is possible to change not only s-wave but also higher partial-wave atom-atom interactions in a cold collision in the presence of relatively intense laser fields tuned near a photoassociative transition.

Arsenic induced toxicity on testicular tissue of mice

Effect of arsenic was studied on the testicular tissue of Swiss albino mice. Sodium-meta-arsenite (NaAsO2) was administered to adult mice (25 +/- 30 g) at a dose level of 30 mg/L and 40 mg/L through drinking water for 30, 45 and 60 days. After the treatment, the testicular organ was removed, weighed and processed for histopathological observation. No change in the body weight was recorded in treated groups after arsenic exposure but significant decrease in the relative testicular weight was observed in comparison with the control. The result showed that arsenic-treated mice exhibited dose dependent gradual reductions in seminiferous tubular diameter and various gametogenic cell population i.e. resting spermatocyte, pachytene spermatocyte and step-7-spermatid except spermatogonia. Leydig cell atrophy was significantly increased in dose dependent manner indicating a definite effect of arsenic on the spermatogenesis in mice. These observations were supported by gradual reduction in Leydig cell population in the above treated groups. In conclusion, the above results confirm the toxic effect of arsenic in testis of mice.

Reproductive effects of ethnomedicinal formulation of tape-vine leaves in female rats

Documented ethno-contraceptive use of Tape-vine or Stephania japonica (THUNB.) MIERS., Syn. Stephania hernandifolia (WILLD.) WALP. leaves is evaluated with regards to post-coital pregnancy interceptive activity of its aqueous extract (AE) and an ethnomedicinal formulation (EF) in Wistar rats. EF at 500 and 250 mg/kg doses induced 66.7% and 33.3% post-coital pregnancy interception respectively and the higher dose exhibited significant reduction in number of litters born and also anti-implantation property. In contrast, none of the dose levels of AE interfered in pregnancy but significant anti-implantation property was observed at doses of 2 and 1 g/kg, even as the higher dose produced significant reduction in number of litters born as well. EF at 500 mg/kg also exhibited significant uterotrophic activity and histological changes in uterus. Pair-wise comparison of sex hormone-levels exhibited significant increment in serum estradiol, LH and FSH but decrease in progesterone levels. Assessed blood lipid-carbohydrate profile exhibited substantial decrease in glucose, cholesterol, VLDL and triglyceride contents and significant increase in HDL. It is concluded that EF probably acts as better post-coital pregnancy interceptive agent through restriction of implantation by alteration of gonadal hormone levels and decline in blood-glucose levels that possibly disrupts oxidative energy metabolism in uterus during implantation. High surge in LH and FSH suggests negligible interference in ovulatory mechanism. This preparation also seems to be free of cardiovascular risk factors. HPTLC and HPLC analysis of both EF and AE exhibited marked chemical differences.

Tea (camelia thea): boon or curse for human being

Drinking some types of tea and other caffaeinated drink is a part of our culture and everyday life. It is contained from the leaves and seeds of evergreen plant (Camelia thea). It is caffeine contained in so many drinks which really plays havoc with our body and mind. It is only when man exceeds they tea drinking that he experiences the ill effects. When taken in limited quantity tea is indeed very good for health.

Epidemiology of peptic ulcer in north Bengal, India

A retrospective analysis of hospital records of inpatients of Medicine department of North Bengal Medical College and Hospital during the period between 1988-90 revealed that 6.2% of all medical admissions were on account of peptic ulcer and or acute gastritis. Duodenal ulcer was prevalent accounting for more than 50% of the cases of peptic ulcer and acute gastritis. Duodenal ulcer was more common in the working age groups (> 21 years) among males and more than 31 yrs among females. Gastric ulcer was more common among older age groups. In respect to ethnicity, Bengali speaking hindus showed high probability for gastric ulcers in both sexes. The probability for duodenal ulcer was within confidence limits among all social groups.

On the Catastrophic Shear Instability in High-Speed Machining of an AISI 4340 Steel

An AISI 4340 Steel (325 BHN) was machined at various speeds up to 2500 m/min (8000 SFPM). Longitudinal midsections of the chips were examined metallurgically to delineate the differences in the chip formation characteristics at various speeds. Chips were found to be continuous at 30 to 60 m/min (100 to 200 SFPM) but discontinuous below this speed. Instabilities in the cutting process, leading to different types of cyclic chip formations, were observed at cutting speeds above 60 m/min (200 SFPM). Fully developed catastrophic shear bands separated by large areas (segments) of relatively less deformed material, similar to that when machining titanium alloys, were observed in the chips at cutting speeds above 275 m/min (800 SFPM). The intense shear bands between the segments appeared to have formed subsequent to the localized intense deformation of the segment in the primary shear zone. As the cutting speed increases, the extent of contact between the segments is found to decrease rapidly. At speeds of 1000 m/min (3200 SFPM) and above, due to rapid intense, localized shear between the segments, these segments were found to separate completely as isolated segments instead of being held intact as a long chip. The speed at which this decohesion occurs was found to depend upon the metallurgical state of the steel machined and its hardness. As in the case of machining titanium alloys, the deformation of the chip as it slides on the tool face, i.e., “secondary shear zone,” appeared to be negligible when machining this AISI 4340 steel at high speed. Based on the metallurgical study of the chip and the similarities of machining this material at high speed and that of titanium alloys at normal speed, a cyclic phenomenon in the primary shear zone is identified as the source of instability responsible for the large-scale heterogeneity and a mechanism of chip formation when machining AISI 4340 steel at high speed is proposed.

In vitro demonstration of seasonal transition effect on acetylcholine liberation from Auerbach's plexus of non-hibernator

Acetylcholine release from Auerbach's plexus of guinea-pig ileum, in vitro, both spontaneous and evoked by field-stimulation, responds to the seasonal transition from the spring to close to the beginning of summer. It did not change during the summer, however, tended to be higher than during the initial period (3 weeks after the beginning of spring).

Evidence against prostaglandin E having a physiological role in acetylcholine liberation from Auerbach's plexus of guinea-pig ileum

The effect of INDO, a PGE synthesis inhibitor, on ACh output from Auerbach's plexus of guinea-pig ileum was investigated. INDO (15-45 mum/ml) failed to alter significantly either spontaneous ACh output or ACh output induced by field stimulation. It is concluded that PGE plays no physiological role in ACh liberation from this tissue.

Dynamic Shear Stress—Analysis of Single Crystal Machining Studies

Experimental results obtained when single crystals of aluminum of known orientation are machined under identical cutting conditions are presented. Analysis of the data obtained shows that the dynamic shear stress remains constant for all orientations tested and is in good agreement with the calculated value for polycrystalline aluminum. The implications of these results to metal cutting theory and the metal physical foundations on which the concept of dynamic shear stress, as a true material property, rests are discussed. The possible role that the dynamic shear stress may play in determining the geometry of the metal cutting problem, a problem in partially constrained plastic flow of metals, is discussed.